also: どやつ
pronoun
Rude or rough masculine pronoun for 'who'. Used in blunt questions or insults, often with a confrontational tone. Not appropriate in polite conversation.
どいつがそんなことを言ったんだ？
Who the hell said that?
お前はどいつだ？
Who the hell are you?
Derived from ど (interrogative prefix) + 奴 (やつ, 'guy, fellow'), with sound change from どやつ to どいつ. The exact historical derivation is uncertain, but it has long been used as a rough interrogative pronoun.