When Is a Noun Not a Noun? When It's an Adjective

You probably know all about the parts of speech and what they do. A verb tells about action. A noun names a person, place or thing. An adjective describes a noun.

These are all pretty straightforward. However, there are also times when a noun functions in a sentence the same way an adjective would, describing another noun.

This is not uncommon when it comes to parts of speech. While some words are always verbs, always nouns or always adjectives, others can change depending on what they do within the sentence.

This is the case for nouns that turn into adjectives, doing the adjective's job of describing something.


noun as adjective example

How Nouns Become Adjectives

"Amusement park" is an example of a phrase where a noun, "amusement," functions as an adjective.

Let's back up and think about the word "amusing." This is an adjective. If you went to an amusing park, you went to a park that was fun in some way.
Now consider the word "amusement," a noun that means something that is fun. However, when you pair "amusement" with "park," the first noun describes the second noun, acting as an adjective. An amusement park is a very specific kind of park, offering rides and games.

Take a look at this sentence. It uses "amusing" as an adjective, "amusement" as a noun turned into an adjective and "amusements" as a noun:

  • "We had an amusing time at the amusement park looking at all of the amusements."

Learning about and understanding parts of speech can be confusing because language is messy. Words don't always fit neatly into categories. For example, just as nouns can become adjectives, some words that look like verbs are also nouns. This is the case for some verbs if you add "ing" to them, creating a noun form known as a gerund.

You can also turn adjectives into nouns. For example, "rich" is usually an adjective, but sometimes it can function as a noun in a sentence, as in

  • "The rich come here for vacation."

You can't just make any adjective into a noun. Not every adjective functions in this way, and furthermore, there are certain rules you must follow when using nouns as adjectives. Those and the examples below will help give you a better understanding of this construction.


Rules and Exception for Nouns as Adjectives

1. The adjective is singular.

Most of the time, the noun as adjective is singular even when the noun is plural. For example, "horse races" describes races involving horses, but the nouns acting as adjective, "horse," remains singular.

Exception

If the noun as adjective is already in plural form as an adjective, it remains in that plural form as a noun. For example, you might find clothes in a clothes closet or, if you have more than one, clothes closets.

2. The noun as adjective always comes before the noun.

3. There can be more than one noun as adjective before the noun.

For example, there might be a "cat health research study." Normally, all of those words are considered nouns, but in this case, all of the nouns are describing the study.

4. There can also be a combination of one or more nouns as adjectives plus an adjective.

The adjective is usually at the beginning of the sentence. If you added this to the example above, you might have a "best cat health research study." Going back to the example of an amusement park in the introduction, you could have an "amusing amusement park."


More Examples of Nouns as Adjectives

It can be helpful to look at more examples of what happens when you turn a noun into an adjective. Here's a list of phrases where only the last word functions as a noun:

  • home run
  • school lunch
  • child car seat
  • killer whale
  • coffee cup

Remember as well that in a construction where nouns become adjectives, you can also have a regular adjective at the beginning:

  • shiny button eyes
  • expensive shoe store
  • old sports injury

Building your vocabulary of adjectives and nouns learning the many ways they can be used helps make your language richer. You can communicate better. After all, you give someone a much more vivid sense of your experience if you say "The dark, humid forest was noisy with birdsong" instead of just "I stood under some trees." When you learn more about different types of adjectives, such as indefinite or quantitative, or about different types of nouns, such as abstract nouns or collective nouns, you can begin using them with even greater confidence.