Who
/huː/
noun
A person under discussion; a question of which person.
pronoun
(interrogative) What person or people; which person or people; asks for the identity of someone. (used in a direct or indirect question)
“I don't know who it is. (indirect question)”
(interrogative) What is one's position; asks whether someone deserves to say or do something.
“I don't like what you did, but who am I to criticize you? I've done worse.”
(relative) The person or people that.