Compound Adjectives: Examples, Types and When to Hyphenate
A compound adjective is two or more words that work together as one adjective to describe a noun: a well-known author, a part-time job, a ten-year-old girl, a sugar-free drink. Before a noun they are usually joined by hyphens, so the reader knows the words belong together; after the noun the hyphen often disappears (the author is well known).
This page shows the common patterns with examples, then the hyphen rules that make compound adjectives readable. For the basics of what any adjective does, start with what is an adjective.
How compound adjectives are formed
| Pattern | Examples | In a sentence |
|---|---|---|
| adjective + noun | full-time, last-minute, high-speed, short-term, long-distance | She found a full-time job. |
| noun + adjective | world-famous, sugar-free, ice-cold, user-friendly | The café serves sugar-free cakes. |
| adjective + -ing participle | good-looking, easy-going, long-lasting, slow-moving | He’s an easy-going boss. |
| adjective + -ed participle | old-fashioned, open-minded, short-sighted, middle-aged | My grandad is very open-minded. |
| adverb + participle | well-known, well-behaved, fast-growing, never-ending | It’s a fast-growing city. |
| noun + -ing participle | record-breaking, mouth-watering, time-consuming, heartbreaking | Filling in the forms was time-consuming. |
| noun + -ed participle | sun-dried, home-grown, child-sized, hand-painted | We bought home-grown tomatoes. |
| number + noun | three-day, five-star, ten-minute, two-bedroom, 50-page | They booked a five-star hotel. |
| number + noun + adjective | ten-year-old, two-metre-long, six-foot-tall | A ten-year-old boy won the prize. |
| adjective + adjective (colours, mixes) | dark-blue, blue-green, red-hot | She wore a dark-blue coat. |
| whole phrases | up-to-date, state-of-the-art, out-of-date, once-in-a-lifetime, one-of-a-kind | It was a once-in-a-lifetime trip. |
Some compounds have fused into single words over time – heartbreaking, waterproof, bittersweet, handmade are now usually written solid. When in doubt, a current dictionary shows how a compound is written today.
Common compound adjectives by use
- Describing people: kind-hearted, warm-hearted, quick-witted, hard-working, self-confident, well-dressed, left-handed, broad-shouldered, blue-eyed, curly-haired.
- Describing places and things: well-lit, run-down, eye-catching, brand-new, second-hand, man-made, high-rise, open-plan, sun-drenched.
- Time and length: short-term, long-term, full-time, part-time, last-minute, year-round, all-day, six-month.
- Work and business: cost-effective, high-quality, customer-focused, data-driven, fast-paced, top-level.
- Food: mouth-watering, home-cooked, low-fat, gluten-free, slow-cooked, sun-ripened. (But freshly baked bread – no hyphen after an -ly adverb; see below.)
Compound adjectives make writing tighter: “a man who works hard” becomes “a hard-working man”; “a walk that lasts three hours” becomes “a three-hour walk”. For more single-word options to describe character and appearance, see descriptive adjectives.
When to hyphenate a compound adjective
Consider two job titles that differ by one mark:
- a small-business owner — someone who owns a small business
- a small business owner — a business owner who is small (physically)
Both are grammatical. Only one is what anyone means. The hyphen is doing the entire job of telling the reader that small attaches to business and not to owner.
The rule in one line
Hyphenate two or more words when they act together as a single adjective in front of a noun.
That is nearly the whole thing. A well-known author. A twentieth-century painting. A three-day weekend. State-of-the-art equipment. In each case the hyphenated cluster is behaving as one unit, and the hyphens say so.
The position test
The same words usually lose their hyphens when they move after the noun, because the ambiguity they were preventing disappears:
- a well-known author → the author is well known
- a two-hour delay → the delay lasted two hours
- an up-to-date record → the record is up to date
Before the noun, the reader has not yet met the noun and needs to know which words are travelling together. After it, the sentence has already resolved and nothing can be misread.
Four things that never take a hyphen
Adverbs ending in -ly. This is the most common error in professional writing. A highly regarded surgeon, not a highly-regarded surgeon. The -ly already signals that the word modifies what follows, so the hyphen adds nothing. No ambiguity is possible: highly cannot attach to surgeon.
Watch for the trap, though. Family, friendly, early and only end in -ly without being adverbs, so a family-run hotel and an early-morning train keep their hyphens.
Compounds that have already fused. Some pairs have been used together for so long that the hyphen has worn away and nobody misreads them: high school student, real estate agent, civil rights movement. Dictionaries record where a given compound has got to, and they do disagree at the margins.
Proper nouns. A New York restaurant, a Middle Eastern dish — the capital letters already bind the words.
Foreign phrases in general use. An ad hoc committee, a bona fide offer. Chicago style leaves these open.
Where it gets genuinely tricky
Numbers and units. Hyphenate before the noun, and drop the plural: a five-mile walk, not a five-miles walk. After the noun it reverts: the walk was five miles.
Suspended hyphens. When two compounds share a second half, the first keeps a dangling hyphen: first- and second-year students, long- and short-term goals. It looks like a typo and is not.
Chains of three or more. A state-of-the-art facility hyphenates throughout. But once a phrase gets long, hyphens stop rescuing it: a hard-to-put-your-finger-on quality is technically correct and unreadable. Rewrite instead.
The cases that actually change meaning
Most hyphen decisions affect polish. These affect sense, and are worth getting right:
- twenty-odd people (about twenty) against twenty odd people (twenty strange people)
- a man-eating shark against a man eating shark
- re-cover the sofa (upholster it again) against recover the sofa (get it back)
- a light-blue dress (pale) against a light blue dress (blue and not heavy)
The working test
Read the first word directly against the noun, skipping the middle one. Small owner? No — so small belongs to business, and the hyphen goes in. Highly surgeon? Not possible, so no hyphen is needed.
If a reader could plausibly attach the first word to the wrong noun, hyphenate. If they could not, you are choosing house style rather than preventing confusion — and either answer is defensible.
Practice
A. Turn each phrase into a compound adjective before the noun.
- a holiday that lasts two weeks
- a man who has a kind heart
- a film that breaks records
- a girl who is eight years old
- a policy that changes quickly (careful)
Answers: 1 a two-week holiday (no plural s). 2 a kind-hearted man. 3 a record-breaking film. 4 an eight-year-old girl. 5 a quickly changing policy (no hyphen after an -ly adverb).
B. Hyphen or not? 1 She is a well(-)known writer. 2 The writer is well(-)known. 3 a highly(-)paid job. 4 an up(-)to(-)date map. 5 The map is up(-)to(-)date.
Answers: 1 well-known (before the noun). 2 well known (after the noun). 3 highly paid (-ly adverb). 4 up-to-date. 5 up to date.
Quick answers
What is a compound adjective? Two or more words acting as one adjective, such as well-known, part-time or ten-year-old.
Do compound adjectives always have hyphens? Usually before the noun, often not after it, and never after an -ly adverb. Some have become single words (waterproof) or stay open by custom (high school student).
Is it “a ten-year-old boy” or “a ten-years-old boy”? “A ten-year-old boy”: the noun inside a compound adjective stays singular. After the noun: “He is ten years old.”
Related: hyphens, en dashes and em dashes, commas between adjectives, participial adjectives and nouns used as adjectives.
Checked against Merriam-Webster, the Chicago Manual of Style and the AP Stylebook. Spotted an error? Tell us — see our editorial policy.
