An indefinite pronoun is a pronoun that refers to an unspecified being, object, or place; e.g. Someone stole my book.
A list of English indefinite pronouns: Another, Anybody, Anyone, Anything, Each, Either, Enough, Everybody, Everyone, Everything, Less, Little, Much, Neither, Nobody, No-one, Nothing, One, Other, Somebody, Someone, Something, Both, Few, Fewer, Many, Others, Several, All, Any, More, Most, None, Some, Such.
The interrogative pronoun is exactly like the indefinite pronoun except the interrogative pronoun always has an accent on the first syllable. Paradigm: