Stage villain not entirely wicked (4)
I believe the answer is:
evil
'wicked' is the definition.
(similar in meaning)
'stage villain not entirely' is the wordplay.
'not entirely' indicates a hidden word.
'EVIL' is hidden in the letters of 'stage villain'.
(Other definitions for evil that I've seen before include "Live badly in depravity" , "heinous" , "Excellent" , "Extremely wicked" , "no good in this puzzle" .)