A word used in place of a noun.
Demonstrative: this, that, these, those
Indefinite: each, either, any, anyone, someone, everyone, few, all, etc.
Intensive: myself, herself, etc.
Interrogative: who, why, how, etc.
Personal: I, you, he, she, it, we, they
Relative: who, whose, whom, that, and compounds such as whoever.