Definitions

1. pronoun

Used to ask for the identity of someone or something.

“Who is at the door?”

2. noun

A person whose identity is not known or specified.

“The police were looking for the who behind the crime.”

3. interrogative

Used to ask a question, especially one that requires a yes or no answer.

“Who will be attending the meeting?”

4. adverb

Used to ask for the identity of someone or something.

“Who do you think will win the election?”