151 Adjectives That Start With U
U is the letter where one prefix does most of the work. 109 of the 151 adjectives below begin un-, and that is the difficulty with this letter rather than a fact about it: English will let you put un- in front of almost anything, and the result is a real adjective that a dictionary will carry and no reader needs explained. Unafraid means not afraid, and there is nothing else to say.
So this page does not list every un- word in the dictionary. It keeps the ones that have drifted away from plain negation and mean something of their own — uncanny, uncouth, unctuous, untoward, unwieldy, unruly, unseemly, unstinting, unwitting — alongside the everyday negations a writer genuinely reaches for.
This page lists 151 adjectives that start with U, each with its meaning. Every one was checked for an adjective entry of its own in Merriam-Webster or Oxford, by reading the part-of-speech markup rather than trusting the page to load. 53 carry a usage label a dictionary actually prints — formal, literary, approving and the rest are the dictionary’s words, not ours. A round bracket reading same sense as is different: that one is our own cross-reference, and it appears when two words on this page really are synonyms and we would rather say so than invent a difference.
The sections below sort by the job the word does rather than by whether it is a compliment, so praise and criticism sit side by side. 49 are not compliments and 24 depend entirely on the sentence, and both are marked. 9 formal or technical words are kept to the end.
All 151 adjectives at a glance
ubiquitous, ugly, ulterior, ultimate, ultrasonic, umber, umbilical, unabashed, unable, unaffected, unanimous, unassuming, unavailing, unaware, unbecoming, unbelievable, unbidden, unbowed, unbridled, uncanny, uncertain, uncharitable, uncharted, unclear, uncomfortable, uncompromising, unconscionable, unconventional, uncouth, unctuous, undaunted, underhanded, understanding, undue, undying, unearthly, uneasy, unemployed, unerring, uneven, unexpected, unfailing, unfair, unfaithful, unfathomable, unfazed, unfeeling, unfettered, unflappable, unflinching, unforgettable, unforgiving, unfortunate, unfriendly, ungainly, ungodly, ungrateful, unhappy, unhealthy, unhinged, unholy, unhurried, unicameral, uniform, unilateral, unimpeachable, uninhibited, unique, united, universal, unjust, unkempt, unkind, unknown, unlikely, unlimited, unlucky, unmitigated, unnatural, unnecessary, unobtrusive, unorthodox, unpalatable, unpleasant, unpredictable, unpretentious, unprincipled, unqualified, unquestioning, unquiet, unrelenting, unreliable, unremitting, unrepentant, unrequited, unruffled, unruly, unsafe, unsavoury, unscathed, unscrupulous, unseemly, unsightly, unsound, unsparing, unspeakable, unstable, unstinting, unsung, untenable, unthinkable, untidy, untimely, untold, untoward, unusual, unvarnished, unwanted, unwavering, unwell, unwieldy, unwilling, unwitting, unwonted, unwritten, unyielding, upbeat, upcoming, upfront, upper, uppity, upright, uproarious, upset, upstanding, uptight, urban, urbane, urgent, urinary, ursine, useful, useless, usual, usurious, uterine, utilitarian, utmost, utopian, utter, uxorious
Describing a person
The largest section, and the one to be most careful with. Unassuming and unpretentious are compliments; uppity and unhinged both carry warnings from the dictionaries themselves, and their entries say so.
| Adjective | What it means |
|---|---|
| ugly | offensive or displeasing to look at (same sense as unsightly) [not a compliment] |
| unabashed | not ashamed or embarrassed by what would embarrass most people, and making no apology for it [depends on the sentence] |
| unable | not having the skill, strength, time or knowledge to do something (rather formal) |
| unassuming | not wanting to draw attention to yourself, your abilities or your status (approving; same sense as unpretentious) |
| unaware | not knowing or realizing that something exists or is happening |
| unbowed | not bowed down or subdued; not defeated, or not ready to accept defeat (literary) |
| uncompromising | not making or accepting a compromise; giving no ground and granting no concessions [depends on the sentence] |
| unconventional | not bound by convention; out of the ordinary in a way that is often striking or interesting (same sense as unorthodox) [depends on the sentence] |
| uncouth | awkward and socially unacceptable in appearance, manner or behaviour; lacking polish and grace [not a compliment] |
| undaunted | courageously resolute in the face of danger or difficulty; not discouraged by setbacks (formal) |
| understanding | sympathetic and tolerant towards other people’s problems, and willing to forgive their mistakes |
| uneasy | feeling anxious or troubled; also, of a silence or a peace, strained and precarious |
| unemployed | of a person, without a paid job though able to work; also, of money or plant, not being put to use |
| unerring | committing no error; always exactly right or accurate |
| unfaithful | not keeping to vows, allegiance or duty; especially, having sex with someone other than your partner [not a compliment] |
| unfazed | not worried or thrown off balance by something surprising or difficult (informal) |
| unfeeling | devoid of feeling; showing no care, kindness or sympathy for other people [not a compliment] |
| unflappable | marked by assurance and self-control; staying calm in a difficult situation (informal) |
| unflinching | not flinching or shrinking; staying strong and steadfast in a difficult or dangerous situation |
| unforgiving | refusing to forgive or excuse a fault; also, of a place or a task, harsh and allowing no mistakes (formal) [not a compliment] |
| unfriendly | hostile or cold towards others; not kind or pleasant in manner [not a compliment] |
| ungainly | lacking smoothness or grace; moving or built in a clumsy, awkward way [not a compliment] |
| ungodly | denying or disobeying God; showing no respect for what is sacred (old-fashioned) [not a compliment] |
| ungrateful | showing no gratitude; not thanking someone for what they have done or given [not a compliment] |
| unhappy | not cheerful or glad; sad, or not pleased with how something has turned out |
| unhinged | highly disturbed and unsteady in mind; not thinking or behaving as one normally would (sometimes offensive) [not a compliment] — Worth knowing: Oxford marks it sometimes offensive, because the sense it defines is having a mental illness. Written about a real person it names an illness as a character flaw. |
| unholy | showing disregard for what is sacred; wicked, or deserving censure [not a compliment] |
| unimpeachable | reliable beyond any doubt; too honest and blameless to be called into question (formal, approving) |
| unkempt | not combed or cared for; messy in hair, dress or general appearance (formal) [not a compliment] |
| unkind | lacking kindness or sympathy; harsh or slightly cruel in what you say or do [not a compliment] |
| unpretentious | free from ostentation or affectation; not trying to seem grander than you are (approving; same sense as unassuming) |
| unprincipled | lacking moral principles; willing to do wrong without any check of conscience (formal; same sense as unscrupulous) [not a compliment] |
| unqualified | lacking the training or knowledge needed; separately, complete and without reservation [not a compliment] |
| unrelenting | not softening or giving way in determination; hard and stern, and never letting up (formal) [depends on the sentence] |
| unreliable | that cannot be trusted or depended on [not a compliment] |
| unrepentant | feeling or showing no shame or regret for what you have done [depends on the sentence] |
| unruffled | calm and composed, especially when things go wrong around you |
| unsavoury | morally offensive, and not the sort of person or business you want to be associated with; also disagreeable to taste or smell [not a compliment] |
| unscrupulous | having no moral principles; ready to cheat or deceive to get what you want (same sense as unprincipled) [not a compliment] |
| unsung | not praised or celebrated, though deserving to be (formal) |
| unwavering | steady and constant; not changing or growing weaker at any point (formal) |
| unwell | in poor health; ill (rather formal) — Worth knowing: Merriam-Webster carries a second sense, labelled euphemistic and somewhat old-fashioned, meaning undergoing menstruation; no dictionary prints an explicit gender label. |
| unwilling | not wanting to do something, and holding back or refusing to do it [depends on the sentence] |
| unwitting | not realizing what you are really doing or what you are caught up in |
| unyielding | firm and often stubborn; refusing to be swayed or to change a decision (formal) [depends on the sentence] |
| upbeat | cheerful and optimistic; giving the sense that things are going to turn out well (informal) |
| uppity | putting on airs of superiority; behaving as though you rank higher than you really do (old-fashioned, informal; disparaging and sometimes offensive) [not a compliment] — Worth knowing: Merriam-Webster prints a usage paragraph recording that this word has a long history of being applied to members of racial minorities and especially to Black people, and says that used that way it is likely to be considered especially offensive. |
| upright | standing vertically rather than leaning or lying flat; of a person, honest and morally sound (same sense as upstanding) |
| upset | emotionally disturbed or agitated; especially, angry or distressed about something |
| upstanding | erect and standing tall; of a person, honest and behaving decently toward others (formal; same sense as upright) |
| uptight | tense, nervous and anxious, often too rigid or touchy to relax (informal) [not a compliment] |
| urbane | polished, poised and socially at ease, with easy good manners — Worth knowing: Oxford marks the sense “(especially of a man)”; Merriam-Webster does not gender it. |
| uxorious | excessively fond of, or submissive to, one’s wife [not a compliment] — Worth knowing: Merriam-Webster defines it only in relation to a wife, so as printed it describes a husband. |
Describing behaviour and speech
What someone did and how they said it, rather than what they are like. Unctuous is the one worth learning here: it describes a manner that is trying to seem sincere and failing, which is a hard thing to say in one word.
| Adjective | What it means |
|---|---|
| ulterior | of a motive or reason: kept hidden behind what is openly admitted, and usually improper [not a compliment] |
| unbecoming | not suiting or flattering the wearer; especially, not fitting the standards expected of a person’s position (formal) [not a compliment] |
| unbidden | happening or arriving without being asked, invited or expected (literary) |
| unbridled | not held in check by any restraint, and so running to extremes (formal, literary) [depends on the sentence] |
| uncharitable | lacking in charity; harsh and severe in judging other people (disapproving) [not a compliment] |
| unclear | hard to understand or make out; not stated definitely enough to be relied on |
| unconscionable | shockingly wrong in its treatment of people; so bad that it should make you ashamed (formal) [not a compliment] |
| unctuous | showing a smug, ingratiating earnestness that is plainly not sincere (formal, disapproving) [not a compliment] |
| underhanded | marked by secrecy and deception; not honest or open in the way it is done [not a compliment] |
| unfailing | constant and never running out; always there and always the same |
| unhurried | moving or done at a relaxed, leisurely pace, with no sign of rush (formal) |
| uninhibited | free from inhibition; expressing yourself openly without worrying what other people think [depends on the sentence] |
| unorthodox | not following established doctrine, custom or practice (same sense as unconventional) [depends on the sentence] |
| unquestioning | given or done without asking questions or showing any doubt or hesitation (formal) [depends on the sentence] |
| unruly | difficult to control, discipline or manage [not a compliment] |
| unseemly | not proper or in good taste for the occasion; below accepted standards of behaviour (old-fashioned or formal) [not a compliment] |
| unsparing | harsh and merciless, holding nothing back in criticism; separately, giving freely and without stint (formal) [depends on the sentence] |
| unstinting | given or giving freely and generously, without holding anything back |
| unvarnished | given plainly, with nothing added to soften or dress it up (formal) |
| upfront | open and direct about what you think or intend, hiding nothing |
Describing a thing, a place or a scene
Objects, places and atmospheres. Uncanny belongs here rather than with the people words — it describes the feeling a place or an event gives you, not a quality someone has.
| Adjective | What it means |
|---|---|
| ubiquitous | existing or found everywhere at once; so common that you keep meeting it wherever you go (formal or humorous) |
| umber | of a dark yellowish brown, the colour of the earth pigment used by painters |
| uncanny | seeming to come from beyond the natural order; strange in a way that is hard to explain |
| uncharted | not recorded or plotted on any map or chart; never visited or investigated before |
| uncomfortable | causing discomfort or annoyance to the body or the mind |
| unearthly | not of this world; strange and eerie in a way that unsettles |
| uneven | not level, smooth or flat; also varying in quality from one part to another [depends on the sentence] |
| unhealthy | not conducive to health; harmful, or showing a lack of good health [not a compliment] |
| uniform | always the same in form, degree or manner; not varying from one part or moment to another |
| unique | being the only one of its kind; having no like or equal |
| universal | covering or affecting all members of a group without limit or exception |
| unknown | not known or identified; whose name, value or nature has not been established |
| unlimited | lacking any controls or bounds; as much or as many as is possible |
| unobtrusive | not attracting attention; present without being noticed or getting in the way (formal, often approving) |
| unpalatable | distasteful to eat or drink; also, of facts or ideas, hard to accept [not a compliment] |
| unsafe | likely to cause harm, damage or loss; dangerous to use, enter or do [not a compliment] |
| unsightly | not pleasing to the sight; offensive to look at (same sense as ugly) [not a compliment] |
| unsound | not healthy or whole; weak, damaged or likely to give way [not a compliment] |
| unstable | not firm or fixed; likely to shift, give way or change suddenly [not a compliment] |
| untidy | not neat or well arranged; left in a mess [not a compliment] |
| unusual | different from what is normal or typical, often in a way that draws attention [depends on the sentence] |
| unwieldy | hard to move, handle or manage because of its size, weight or complexity [not a compliment] |
| upper | higher in position, rank or order than something else |
| uproarious | very noisy, with loud laughter or disorder; also extremely funny |
| urban | of or relating to a city or town rather than the countryside |
| useful | able to be put to use; serving a real purpose or helping you get something done |
| useless | of no use at all; failing to do or achieve what is needed [not a compliment] |
Describing a situation or an outcome
How things stand and how they turned out. This is where the plain negations earn their place: unavailing, untenable and unmitigated say precisely what a longer phrase would.
| Adjective | What it means |
|---|---|
| ultimate | last in a progression or series; coming at the end of a long process |
| unaffected | not changed or influenced by something; separately, natural and sincere in manner (approving in the ‘natural and sincere’ sense) |
| unanimous | agreed on or shared by everyone in a group, with nobody dissenting |
| unavailing | achieving nothing despite the effort put in; without success (formal) |
| unbelievable | too improbable to be believed; also, so extreme in degree that it is hard to credit (informal in the ‘so extreme it is hard to credit’ sense) [depends on the sentence] |
| uncertain | not known beyond doubt; or, of a person, feeling doubt and not yet sure |
| undue | more than is reasonable or necessary; exceeding what is proper (formal) [not a compliment] |
| undying | never coming to an end; lasting for ever [depends on the sentence] |
| unexpected | not expected or foreseen; coming as a surprise |
| unfair | marked by injustice, partiality or deception; not treating people equally (same sense as unjust) [not a compliment] |
| unfathomable | too deep to be measured; too strange or difficult to be understood (formal) |
| unfettered | not controlled or restricted in any way; free of limits (formal) |
| unforgettable | impossible to forget, for good reasons or bad [depends on the sentence] |
| unfortunate | having bad luck, or caused by bad luck (same sense as unlucky) [depends on the sentence] |
| unilateral | done or undertaken by one party alone, without the agreement of the others involved [depends on the sentence] |
| united | made one; joined together as a single body or by shared aims |
| unjust | not deserved or fair; marked by injustice (same sense as unfair) [not a compliment] |
| unlikely | not likely to happen or to be true; improbable |
| unlucky | having or bringing bad luck; marked by adversity or failure (same sense as unfortunate) |
| unmitigated | not lessened or relieved in any degree; complete, and almost always of something bad [not a compliment] |
| unnatural | not in accordance with nature or with the normal course of events [not a compliment] |
| unnecessary | not needed, or more than is needed [not a compliment] |
| unpleasant | not agreeable; causing displeasure or distaste [not a compliment] |
| unpredictable | not able to be known in advance, because it changes or depends on too many things [depends on the sentence] |
| unremitting | never stopping or easing off; going on constantly without a break (formal) [depends on the sentence] |
| unrequited | not returned or reciprocated, especially of love for someone who does not love you back (formal) |
| unscathed | completely unharmed, having come through danger or trouble without injury |
| unspeakable | beyond what words can express; most often of something inexpressibly bad, but also of joy too great to describe (literary, usually disapproving) [not a compliment] |
| untenable | impossible to defend against attack or criticism; not able to be held on to (formal) [not a compliment] |
| unthinkable | impossible to imagine or accept; out of the question [depends on the sentence] |
| untimely | coming at the wrong moment, or sooner than is normal or proper (formal) [depends on the sentence] |
| untold | not told or made known; also too great or too many to be counted |
| untoward | hard to guide or manage; also out of the ordinary and unwelcome (formal) [not a compliment] |
| unwanted | not wanted or needed by anybody |
| unwonted | out of the ordinary, and not what anyone expected (formal) |
| unwritten | not set down in writing, but known and followed all the same |
| upcoming | due to happen soon; coming up in the near future |
| urgent | needing to be dealt with straight away |
| usual | in line with custom or habit; what normally happens or is normally done |
| utmost | furthest or most extreme; of the greatest possible degree or amount |
| utopian | belonging to an imagined perfect society; ideal in a way that could not really exist [depends on the sentence] |
| utter | absolute and complete, taken to the highest possible degree |
Formal, technical and rare
The formal and technical end, kept separate so it can be skipped. A short section for this letter, because U’s difficulty is the prefix rather than the Latin.
| Adjective | What it means |
|---|---|
| ultrasonic | of sound waves: above the pitch the human ear can hear, roughly beyond 20,000 hertz |
| umbilical | of, relating to, or used at the navel |
| unicameral | having a single legislative chamber rather than two (specialist) |
| unquiet | not calm; agitated, restless or troubled (literary) |
| urinary | relating to urine and the organs that form and discharge it |
| ursine | of or relating to bears; having the look or manner of a bear (specialist or literary) |
| usurious | lending money at rates of interest so high as to be exploitative (formal) [not a compliment] |
| uterine | born of the same mother but a different father; also, of or relating to the womb |
| utilitarian | relating to utilitarianism, the greatest good for the greatest number; also, plain and practical rather than decorative (formal) |
Positive and negative at a glance
Sorting by job rather than by tone means compliments and criticisms sit side by side above. Here a selection of them is separated into three columns, using words already defined on this page — and the third column is the interesting one.
| Clearly positive | Clearly negative | Depends on the sentence |
|---|---|---|
| unassuming, unbowed, undaunted, understanding, unerring, unfailing, unfazed, unflappable, unflinching, unhurried, unimpeachable, unique, united, unobtrusive | ugly, ulterior, unbecoming, uncharitable, unconscionable, uncouth, unctuous, underhanded, undue, unfair, unfaithful, unfeeling, unforgiving, unfriendly | unabashed, unbelievable, unbridled, uncompromising, unconventional, undying, uneven, unforgettable, unfortunate, unilateral, uninhibited, unorthodox, unpredictable, unquestioning |
The third column is where the letter is most interesting. Unbridled, uncompromising and unabashed all describe someone who will not moderate themselves, and whether that is praise or complaint is decided entirely by the sentence around them. Reach for one of these in a reference and the reader will supply the verdict you did not.
Using them in a sentence
- Her manner was unassuming, which is exactly why the room kept underestimating her.
- The delay was unfortunate; the excuse offered for it was unconscionable.
- He stayed unfazed while the rest of us were visibly uneasy.
- The ground ahead is uncharted, and the schedule frankly untenable.
- A cook who is unhurried is not at all the same as one who is unwilling.
- The vote was unanimous, and the reason for it stayed unwritten.
Words people get wrong
| Pair | The difference that matters |
|---|---|
| uninterested / disinterested | The pair both dictionaries built apparatus for, and neither word is on this page. Uninterested means not interested. Disinterested means impartial, with no stake in the outcome. Merriam-Webster prints a usage guide on both entries recording that the two started out meaning the opposite of what they mean now: disinterested once meant not interested and uninterested once meant not biased. Its verdict on using disinterested for uninterested is careful: it will incur the disapproval of some who may not appreciate the word’s history or the subtleties of its present use. That is a long way from a prohibition, and Oxford records the use plainly, marked informal. |
| urban / urbane | One letter apart, counted. Urban is of a town or a city. Urbane is polished and socially at ease — and Oxford prints especially of a man on it, which is worth knowing before using it about a woman. They are not strangers, either: Merriam-Webster notes that urbane once meant urban, both from the Latin urbanus. |
| unique / unusual | The argument about whether anything can be very unique, and the dictionary does not take the side you expect. Merriam-Webster prints a usage paragraph on exactly this and concludes that the objection fails, because unique also means unusual or rare — its third sense is very special or notable: unusual. In that sense very unique is standard. Reserve the objection for the one-of-a-kind sense, where it holds. |
| unexceptional / unexceptionable | Two letters apart, not one. Unexceptional is ordinary, nothing special. Unexceptionable is beyond criticism, giving no grounds for objection — Oxford marks it formal. The catch is that the wall between them is not solid: Oxford gives unexceptionable a second sense, marked informal, meaning not very new or exciting. So the two do overlap, in the direction people assume is the error. |
| unsociable / unsocial | Neither is on this page, and the three-way with antisocial is the only place where a regional label in this letter attaches to the sense people actually argue about. The working-hours sense is genuinely British: Oxford gives unsocial as outside the normal times of working, marked British English, and Merriam-Webster labels unsocial hours British too. The not-friendly senses carry no regional label at all. And they are not cleanly separable: Merriam-Webster defines antisocial in its first sense as unsociable. It is not quite the only British label in the letter — unsafe carries one on a legal sense — but it is the only one attached to a whole word. |
Related guides
- Adjectives for unique — the synonyms, for when one word is carrying too much weight.
- Adjectives for the universe — where unfathomable and uncharted do their most natural work.
- Adjectives for a university — a subject this letter only touches, since most of that vocabulary is not U.
- Adjectives for a unicorn — for unearthly and the rest of that register.
- Adjectives that start with T — the letter before, and a much larger one.
- Adjectives that start with V — the letter after, where the difficulty is Latin rather than a prefix.
Checked against Merriam-Webster, the Chicago Manual of Style and the AP Stylebook. Spotted an error? Tell us — see our editorial policy.
