Jealous character to return greeting (7)
I believe the answer is:
othello
'jealous character' is the definition.
(I've seen this before)
'to return greeting' is the wordplay.
'return' shows that the letters should be reversed in order.
'greeting' becomes 'hello' (hello is a kind of greeting).
'to' backwards is 'ot'.
'ot'+'hello'='OTHELLO'
(Other definitions for othello that I've seen before include "As part" , "Old Black Ram!" , "Hello to Shakespeare's tragic hero" , "product of 12 [SHAKESPEARE] , inspiring 6 [VERDI]" , "Shakespeare tragedy" .)