What Are Compound Adjectives?
Compound adjectives are adjectives made up of two or more words that work together as a single unit to describe a noun. They are usually connected by a hyphen when they appear before the noun they modify. Instead of saying "a building that has twenty storeys," we can say "a twenty-storey building." Instead of "a child who is five years old," we say "a five-year-old child." Compound adjectives allow us to pack more information into fewer words, making our English more concise, natural, and sophisticated.
Compound adjectives are everywhere in English — in newspapers, advertisements, academic texts, and everyday conversation. You will encounter them in job descriptions (full-time position), product labels (sugar-free drink), weather reports (record-breaking temperatures), and countless other contexts. They are formed from many different word combinations: adjective + noun, adjective + participle, noun + participle, number + noun, and more.
The most important thing to remember about compound adjectives is the hyphen. The hyphen is not optional decoration — it is a critical signal that tells the reader these words form a single adjective. Without the hyphen, the meaning can change dramatically or become confusing.
Compare these two phrases:
a small business owner = the owner of a small business
a small-business owner = an owner of a small business (same, but clearer)
But consider:
a man eating shark = a man who is eating shark (for dinner)
a man-eating shark = a shark that eats men!
The hyphen tells the reader which words belong together.
When Do We Use Compound Adjectives?
Compound adjectives are used whenever we want to describe a noun using a multi-word modifier that expresses a single, unified concept:
| Context | Example | Why Use a Compound? |
|---|---|---|
| Describing age | a three-year-old girl | More concise than "a girl who is three years old" |
| Describing appearance | a blue-eyed woman | Creates a vivid image in fewer words |
| Describing behaviour | a well-behaved student | Combines manner + participle elegantly |
| Describing size/quantity | a fifty-page report | Efficient way to express measurement |
| Describing duration | a two-hour flight | Packs time information into the adjective |
| Describing quality | a high-quality product | Standard descriptive combination |
Number-Based Compound Adjectives
One of the most common and most important types of compound adjective involves numbers. These are used constantly to describe age, duration, measurement, and quantity:
Number + singular noun + (noun being described)
The noun in the compound is always singular, even when the number is plural. This is one of the most common mistakes learners make.
| Type | Compound Adjective | Full Sentence |
|---|---|---|
| Age | five-year-old | She has a five-year-old daughter. |
| Duration | three-hour | We watched a three-hour documentary about climate change. |
| Distance | ten-kilometre | He completed the ten-kilometre race in under forty minutes. |
| Size | twenty-storey | They are building a new twenty-storey office tower downtown. |
| Quantity | two-hundred-page | I had to read a two-hundred-page manual before starting the course. |
| Cost | fifty-dollar | He was wearing a fifty-dollar watch that looked like a thousand. |
When a number + noun combination is used as a compound adjective, the noun is always singular:
✘ a five-years-old child
✔ a five-year-old child
✘ a three-hours flight
✔ a three-hour flight
Compare: "The child is five years old." (predicate — plural is correct) vs "a five-year-old child" (compound adjective — always singular).
Adjective/Adverb + Participle Compounds
Another extremely common pattern combines an adjective or adverb with a present participle (-ing) or past participle (-ed):
Adjective/Adverb + present participle (-ing)Adjective/Adverb + past participle (-ed / V3)
| Pattern | Compound Adjective | Example |
|---|---|---|
| Adj + -ing | good-looking | He is a very good-looking man with dark eyes. |
| Adj + -ing | easy-going | Our new manager is really easy-going and friendly. |
| Adj + -ing | long-lasting | This paint provides a long-lasting finish for outdoor surfaces. |
| Adv + -ed | well-known | She is a well-known author who has published over twenty novels. |
| Adv + -ed | badly-damaged | The badly-damaged building was finally demolished last year. |
| Adj + -ed | old-fashioned | My grandmother still uses an old-fashioned typewriter. |
| Adv + -ed | well-dressed | The well-dressed gentleman entered the room confidently. |
| Adj + -ed | narrow-minded | A narrow-minded approach to education limits student creativity. |
Noun-Based Compound Adjectives
Compound adjectives can also be formed by combining a noun with an adjective, participle, or another noun:
| Pattern | Compound Adjective | Example |
|---|---|---|
| Noun + adj | world-famous | The city is home to several world-famous museums. |
| Noun + -ing | time-consuming | Filling out government forms can be very time-consuming. |
| Noun + -ing | breath-taking | We enjoyed the breath-taking views from the mountain summit. |
| Noun + -ed | hand-made | Each piece is a hand-made creation by local artisans. |
| Noun + -ed | sun-dried | The salad was topped with sun-dried tomatoes and fresh basil. |
| Noun + noun | part-time | She found a part-time job at a bookshop near the university. |
| Adj + noun + -ed | blue-eyed | The blue-eyed boy smiled at the camera with pure innocence. |
| Adj + noun + -ed | open-minded | She is one of the most open-minded people I have ever met. |
A very productive pattern uses adjective + body part + -ed to describe people and animals:
blue-eyed, long-legged, short-haired, broad-shouldered, left-handed, bare-footed
These compounds always use -ed (not -ing) and always take a hyphen before the noun.
Special Rules and Notes
| Rule | Explanation | Example |
|---|---|---|
| Hyphen before noun | Compound adjectives are hyphenated when they come before the noun | a well-known actor |
| No hyphen after noun | When they come after the noun, the hyphen is often dropped | The actor is well known. |
| -ly adverbs: no hyphen | If the first word ends in -ly, no hyphen is needed | a beautifully designed website |
| Never add -s to the noun part | The noun inside a compound adjective stays singular | a five-star hotel (not five-stars) |
| Some are permanent | Some compound adjectives are so common they are always written with a hyphen | full-time, part-time, up-to-date, well-known |
| Self- compounds | Compounds with "self" always use a hyphen | self-confident, self-employed, self-taught |
When the first word of the compound is an adverb ending in -ly, do not use a hyphen:
✘ a highly-respected professor
✔ a highly respected professor
✘ a newly-built house
✔ a newly built house
The -ly ending already signals that it modifies the next word, so the hyphen is unnecessary. However, "well," "ill," "best," and "least" are not -ly adverbs, so they do take a hyphen: a well-paid job.
A compound adjective is a small miracle of efficiency — two or three words, joined by a tiny hyphen, doing the work that would otherwise require an entire clause.
— The Grammar GazetteExample Sentences
Compounds with Free, Proof, and Like
Several English suffixes and combining forms produce large families of compound adjectives. Three of the most productive are -free, -proof, and -like:
| Suffix | Meaning | Examples |
|---|---|---|
| -free | without, not containing | sugar-free, gluten-free, duty-free, smoke-free, stress-free, risk-free |
| -proof | resistant to, protected from | waterproof, bulletproof, fireproof, soundproof, foolproof, shockproof |
| -like | resembling, similar to | childlike, lifelike, dreamlike, businesslike, ladylike, warlike |
| -friendly | suitable for, easy to use | user-friendly, eco-friendly, family-friendly, budget-friendly |
| -worthy | deserving of | trustworthy, newsworthy, praiseworthy, noteworthy, roadworthy |
English is very flexible with compound adjectives. Once you understand the patterns, you can create new compounds that native speakers will understand immediately:
a cloud-covered sky, a battery-powered device, a chocolate-flavoured milkshake
If two or more words together describe a single quality of a noun, they can often form a compound adjective.
Common Mistakes
✘ a ten-years-old building
✔ a ten-year-old building
✘ a three-hours delay
✔ a three-hour delay
Nouns inside compound adjectives are always singular.
✘ a well known artist (ambiguous)
✔ a well-known artist (clear compound adjective)
Before the noun, always use a hyphen. Without it, the reader may parse the words differently.
✘ a recently-published book
✔ a recently published book
Adverbs ending in -ly do not need a hyphen because the -ly suffix already shows they modify the next word.
Before noun (attributive) → hyphen: a well-paid job
After verb (predicative) → usually no hyphen: The job is well paid.
The position of the adjective determines whether the hyphen is needed.
✘ a made-hand scarf
✔ a hand-made scarf
✘ a breaking-record speed
✔ a record-breaking speed
The word order in compound adjectives follows specific patterns. Learn common compounds as fixed expressions.
Types of Compound Adjectives: Complete Reference
Here is a comprehensive overview of all major compound adjective patterns in one reference table:
| Pattern | Structure | Examples |
|---|---|---|
| Number + Noun | number-noun (singular) | five-star, two-hour, ten-page |
| Adj + Noun | adjective-noun | full-time, long-term, high-speed |
| Adj + -ing | adjective-Ving | good-looking, easy-going, long-lasting |
| Adj + -ed | adjective-Ved | old-fashioned, narrow-minded, short-sighted |
| Adv + -ed | adverb-Ved | well-known, well-paid, badly-damaged |
| Noun + -ing | noun-Ving | time-consuming, heart-breaking, mouth-watering |
| Noun + -ed | noun-Ved | hand-made, sun-dried, air-conditioned |
| Adj + Noun + -ed | adj-noun-ed | blue-eyed, open-minded, kind-hearted |
| Noun + Adj | noun-adjective | world-famous, ice-cold, sky-high |
| Self- compounds | self-adjective | self-confident, self-employed, self-taught |
The best way to learn compound adjectives is to notice them when you read or listen to English. Keep a notebook of compound adjectives you encounter and group them by pattern. Over time, you will develop an intuition for which combinations sound natural and which do not. Start with the most common ones (well-known, old-fashioned, part-time, full-time, good-looking) and expand from there.
Before a noun: Use a hyphen → a well-known author
After a noun (predicative): Often no hyphen → The author is well known.
First word ends in -ly: No hyphen → a recently published book
Self- compounds: Always hyphenated → self-confident
Number + noun: Always hyphenated before noun → a three-hour delay
When in doubt, use the hyphen. It is always better to add clarity than to risk confusion.