Indefinite adjectives give nonspecific information about a noun. For example, the indefinite article fewindicates some, but not an exact amount. Indefinite adjectives are easily confused with indefinite pronouns since they are the same words used differently. An indefinite pronoun replaces a noun. An indefinite adjective precedes a noun or pronoun and modifies it. It is important for you to understand the difference between indefinite adjectives and pronouns to assure you are saying what you mean. Some common indefinite adjectives include all, any, anything, each, every, few, many, one, several,some, somebody, and someone.
Example
Indefinite adjective: We are having some cake for dessert.
Indefinite pronoun: I like cake. I’ll have some, please.
Indefinite adjective: You can find a state name on each quarter.
Indefinite pronoun: I have four Illinois quarters, and each is brand new.
Adapted from Appendix A, “Writing for Nonnative English Speakers” in Writer’s Handbook v 1.0 used according to Creative Commons CC BY-NC-SA 3.0