who

pronoun; possessive whose; objective whom.

1. what person or persons?: Who did it?
2. (of a person) of what character, origin, position, importance, etc.: Who does she think she is?
3. the person that or any person that (used relatively to represent a specified or implied antecedent): It was who you thought.
4. (used relatively in restrictive and nonrestrictive clauses to represent a specified antecedent, the antecedent being a person or sometimes an animal or personified thing): Any kid who wants to can learn to swim.
5. Archaic. the person or persons who.