What Is an Indefinite Pronoun?

An indefinite pronoun is a pronoun that refers to an unspecified or unidentified person or thing. It's vague rather than specific, and it doesn't have an antecedent.

Indefinite pronouns include quantifiers (some, any, enough, several, many, much); universals (all, both, every, each); and partitives (any, anyone, anybody, either, neither, no, nobody, some, someone). Many of the indefinite pronouns can function as determiners. Positive indefinite pronouns ending in -body can be interchanged with those that end with -one, such as anybody and anyone.

Types of indefinite pronouns fit two categories: those that are made up of two morphemes and are called compound pronouns, such as somebody, and those that are followed by the word of, called of-pronouns, such as all or many. 

Singular Indefinite Pronouns

Most indefinite pronouns take singular verbs, either because they represent one thing or because they are collective, and, like collective nouns, agree with singular verbs and pronouns. For example:

• Neither of us is available for the committee.
• Each member of the family has the flu.
• Everyone works well together.
• Someone came into the room looking for her water bottle.
• Everybody kept the information on the surprise to him or herself.
• Either option presents its own challenges.

The disagreement of the singular collective pronouns with pronouns in the predicate is one of the most common errors in formal, written English because informal, spoken English doesn't always adhere to the rule. In informal speech, someone would likely say, "Everybody kept the information on the surprise to themselves," and no one would find a reason to correct the speaker, because the context is clear. 

Plural and Variable Indefinite Pronouns

Plural indefinite pronouns take plural verbs. For example:

• Both of us match the description. 
• Many were hoping for a better outcome.
• Few were optimistic about this ballgame.

Variable indefinite pronouns (all, any, more, most, none, some) can go with either a plural or a singular verb, based on what noun they're talking about. Can you count what's being talked about? Then use a plural verb. For example:

• Most employees are getting a raise. 
• All the ice is gone.
• Some ice cubes are in that cooler. 
• Any experience is beneficial to the job. 
• Some of his sadness practically feels tangible.

Prepositional Phrases

Watch out when you've got prepositional phrases separating your subject and your verb. Here, each is the subject of the sentence, not friends, so the sentence takes a singular verb. Each is always singular.

• Each of her friends wants a different team to win.

When you have a prepositional phrase following a variable pronoun, what is in the phrase helps determine which type of verb you'll need.

• Most of the bricks were loose on that wall.
• Some of the food was past its expiration date.

List of Indefinite Pronouns

all
any
anybody
anyone
anything
both
each
either
everything
enough
everybody
everyone
few
many
most
much
neither
no one
nobody
none
nothing
several
some
somebody
someone
something

Sources

• Ron Cowan, The Teacher's Grammar of English. Cambridge University Press, 2008
• Penelope Choy and Dorothy Goldbart Clark, Basic Grammar, and Usage, 8th ed. Wadsworth, 2011
• Randolph Quirk et al., A Comprehensive Grammar of the English Language. Longman, 1985
• Andrea B. Geffner, Business English: The Writing Skills You Need for Today's Workplace, 5th ed. Barron's, 2010