Tragic villain DiMaggio regularly ignored (4)
I believe the answer is:
iago
'tragic villain' is the definition.
(I've seen this in another clue)
'dimaggio regularly ignored' is the wordplay.
'regularly ignored' means one should take alternating letters (letters removed at regular intervals).
The alternating letters of 'dimaggio' are 'IAGO'.
(Other definitions for iago that I've seen before include "Shakespeare's jealous villain" , "Evil character in Othello" , "Othello's Ancient" , "Organ stop" , "Othello's evil counsellor" .)