In English texts and verbal communication, the word “who” is always used as a pronoun.

1. Pronoun

In all cases, the word “who” acts as a pronoun because it can take the place of a noun. It can be used to ask a question about which person, or it can also start the clause that provides additional details regarding someone. For instance, in the sample sentence below:

That is the woman who gave me the address.

The word “who” is used to introduce the clause that provides further information about the “woman.”

Definition:

a. what or which person or people

• Example:
• Who is that man?

b. used to introduce a clause giving further information about a person or people previously mentioned

• Example:
• Christopher plays the teenager who killed his own parents.