An indefinite pronoun is a pronoun that relates to an unspecified or unknown person or thing. It’s vague rather than specific and doesn’t have an ancestor.
Indefinite pronouns involve quantifiers (some, any, enough, several, many, much), universals (all, both, every, each), and partitives (any, anyone, anybody, either, neither, no, nobody, some, someone). In addition, many indefinite pronouns can function as determiners. For example, positive indefinite pronouns ending in the body can be substituted with those that end with –one, such as anybody and anyone.
Types of indefinite pronouns fit two types: those that are made up of two morphemes called compound pronouns, such as somebody, and those that are followed by the word of, called of pronouns, such as all or many.
