What an indefinite adjective is
An indefinite adjective describes a noun in a non-specific way. It tells you roughly how much or how many, or which one, without giving an exact number or naming a particular item.
- Some students arrived early.
- She did not eat any dessert.
- Several cars were parked outside.
The word always comes before a noun (or a noun phrase) and modifies it. Many modern grammars classify these words as determiners or quantifiers rather than adjectives, so you may see both terms. The traditional label “indefinite adjective” is still widely used in schools.
Common indefinite adjectives
| Group | Words |
|---|---|
| Whole or large amounts | all, most, much, many, enough |
| Small amounts | few, little, less, fewer, several |
| Some or none | some, any, no |
| One of a group | each, every, either, neither, another |
| Two together | both |
| Difference or type | other, certain, various |
Lists differ between sources, and some words (such as every or no) are called determiners in many references. That is fine: the key test is whether the word sits before a noun and gives non-specific information about it.
Example sentences
Here are ten sentences, with the indefinite adjective in bold.
- Many people enjoy walking in the park.
- Few students finished the exam early.
- Some birds migrate thousands of miles.
- Do you have any questions?
- Each player received a medal.
- Several reasons explain the delay.
- Most children like stories.
- We did not have much time.
- Both answers are correct.
- Another option is to wait until tomorrow.
Indefinite numeral adjectives
People sometimes search for “indefinite numeral adjectives”. These are indefinite adjectives that express quantity without a precise number, such as few, many, several, some, all and enough.
- Few tickets remain.
- Many houses lost power.
- Several teams entered the contest.
- There is enough food for everyone.
They contrast with definite numerals such as three or twenty, which give an exact count.
Indefinite adjective or indefinite pronoun?
The same word can be an adjective in one sentence and a pronoun in another. Look at whether a noun follows.
| Sentence | Role of “several” |
|---|---|
| Several people were waiting. | Adjective (modifies “people”) |
| Several were waiting. | Pronoun (stands alone) |
More examples:
- I saw some cartoons. (adjective)
- I saw some. (pronoun)
- Many voted against it. (pronoun)
- Many members voted against it. (adjective)
Some words, such as everyone or nobody, are only pronouns, so they never work as indefinite adjectives. For more on how pronouns that stand in for people in general behave, see our guide to impersonal pronoun examples.
Are “a” and “an” indefinite adjectives?
Not usually. “A” and “an” are called indefinite articles, and articles are treated as their own small class (or as determiners). They are indefinite because they refer to any one member of a group rather than a specific one.
Ten sentences with indefinite articles:
- She bought a book.
- He ate an apple.
- I need a pen.
- They saw an owl.
- We stayed in a hotel.
- She is an engineer.
- Please bring a blanket.
- It was an easy test.
- He wants a bicycle.
- I heard a noise.
Use a before a consonant sound and an before a vowel sound (an hour, a university).
Agreement: singular, plural and uncountable nouns
Different indefinite adjectives pair with different kinds of nouns. Getting this wrong is a classic error in identifying sentence errors exercises, for example each of the players have.
- Singular countable: each, every, another, either, neither (each student)
- Plural countable: few, many, several, both, fewer (many students)
- Uncountable: much, little, less (much water)
- Either: some, any, all, most, more, enough (some water, some students)
A traditional guideline is to use fewer with plural nouns and less with uncountable nouns: fewer mistakes, less sugar. In everyday speech the two are often mixed, but the distinction is the one most style guides still recommend in formal writing.
Modern grammar: determiners and quantifiers
Many contemporary grammars place these words in the determiner class, with quantifier as a sub-type. This matters little for everyday writing, but if a textbook or exam uses “determiner”, it is describing the same words. The practical rule is the same: they come before a noun and indicate amount or selection without precision.
Quick practice
Which sentences use an indefinite adjective? (Answers follow.)
- Some of the cake is left.
- Some cake is left.
- Many were disappointed.
- Many fans were disappointed.
Answers: In 2 and 4 the word modifies a noun (adjective use). In 1 and 3 the word stands alone as a pronoun, since “Some of the cake” and “Many” work as noun-like units.
Summary
Indefinite adjectives such as some, any, few, many, several and each describe nouns without being exact. If the word is followed by a noun, it is working as an adjective; if it stands alone, it is a pronoun. Match the word to the type of noun, and remember that “a” and “an” belong with the articles.