For today’s grammar lesson, we are going to learn about compound adjectives. These are groups of words that come together to function as an adjective. They are usually joined by a hyphen.

What is a Compound Adjective?

A compound adjective is a group of words (at least two) that work together to function as an adjective. Most commonly, you will see two adjectives prior to a noun. For example:

  • part-time job
  • world-famous actor

In these examples “part-time” and “world-famous” are compound adjectives. They are both made up of two words but they function together as one adjective.

list of compound adjectives

Rules for Compound Adjectives

A compound is when several words come together to make a single new word. When that happens with a compound adjective, then two (or more) words will be joined to make a single adjective, such as:

  • all-time high
  • first-place prize
  • six-year-old boy
  • twentieth-century values

In each of these examples, we have several words joined by hyphens functioning as adjectives (all-time, first-place, six-year-old, twentieth-century). These come before a noun.

Compound adjectives don’t always come before a noun. They may appear as predicate adjectives, meaning that they come later in the sentence, after a linking verb. A very common linking verb is “to be,” so let’s look at an example:

  • I spoke to a middle-aged man.
  • The man was middle-aged.

In the first example, the compound adjective (“middle-aged”) comes before the noun but in the second it comes after the noun and is linked to it by a verb (“was”).

You will see that most of these examples feature two words joined by a hyphen but I did include a three-word adjective above (“six-year-old”). This is quite common with numbers and specifically ages:

  • forty-two-year-old man
  • twelve-year-old girl

Just remember that each of the words that work together to modify the noun is considered one adjective.

Do compound adjectives always require a hyphen?

Compound adjectives usually have a hyphen but not always. There are a few exceptions.

Firstly, we do not hyphenate a compound adjective when the first of those words is an adverb. For example:

  • highly recommended programme
  • really handsome guy
  • very interesting person

Some people like to remember this by saying that we do not hyphenate when the first word ends in “-ly” but as we can see from the third example, that’s not strictly true. Not all adverbs end in “-ly.”

If the words used as an adjective make up a proper noun (ie the official name of something), then we do not hyphenate them:

  • These books have a Harry Potter feel.
  • The party will have an Ancient Egypt theme.

In these examples, some people might be tempted to hyphenate the words that have become adjectives (Harry Potter, Ancient Egypt), but this would be incorrect.

There are also some instances of compound adjectives where two words have already become one word:

  • overzealous approach
  • undercooked chicken

However, these are actually considered single words (even though they’re made of separate words) and so they are a little different.

Comparatives and Superlatives

When the first word in a compound adjective is comparative or superlative, we hyphenate it when it comes prior to a noun but we do not hyphenate it when it comes later in the sentence. For example:

  • We all agreed it was the best-tasting dish on the menu.
  • This dish is the best tasting.

When this compound adjective (“best-tasting”) came before the noun it modified (“dish”), it was hyphenated. When it came after, it was not hyphenated.

Examples of Compound Adjectives

Here is a list of compound adjectives:

Compound AdjectiveExample (with noun)
all-timeall-time high, all-time low
blue-collarblue-collar workers
brand-newbrand-new car, brand-new shoes
child-likechild-like innocence
double-sideddouble-sided tape
eco-friendlyeco-friendly design, eco-friendly resort
English-speakingEnglish-speaking country
eye-catchingeye-catching design, eye-catching colours
eye-openingeye-opening experience
first-placefirst-place prize
gender-neutralgender-neutral bathroom, gender-neutral clothing
good-lookinggood-looking man, good-looking person
half-heartedhalf-hearted attempt
high-levelhigh-level competition, high-level debate
long-lastinglong-lasting flavour
middle-agedmiddle-aged man, middle-aged woman
mouth-wateringmouth-watering chicken, mouth-watering recipe
narrow-mindednarrow-minded person
part-timepart-time job, part-time worker, part-time schedule
short-termshort-term loan, short-term success
sugar-freesugar-free gum, sugar-free snack
sun-driedsun-dried tomatoes, sun-dried raisins
ten-year-oldten-year-old boy
top-of-the-linetop-of-the-line product
well-educatedwell-educated person
well-knownwell-known actor, well-known place

Examples of Compound Adjectives with Numbers

It is quite common to see compound adjectives used with heights and weights:

  • A two-ton truck.
  • A six-foot man.
  • A ten-gallon hat.

Note that the measurement is in singular form. This is an important rule. Even though we would say, for example, “ten gallons,” we use the singular form when it becomes a compound adjective. (You can learn more about numbers and IELTS here.)

Other examples include:

  • one-of-a-kind experience
  • first-of-its-kind product
  • seven-fold increase
  • two-time champion

Of course, as we have seen above, we frequently use compound adjectives with ages:

  • A six-year-old boy appeared from nowhere and asked us a question.
  • We were approached by a thirty-one-year-old male who appeared confused and aggressive.
  • A sixty-four-year-old man died last night.
  • The police found a two-month-old baby.