Othello villain (4)
I believe the answer is:
iago
'othello villain' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for iago that I've seen before include "Othello's nemesis" , "Organ stop" , "Othello's evil counsellor" , "Othello's treacherous officer" , "Evil character in Othello" .)