Wickedness in a revolutionary is abused (7)
I believe the answer is:
reviled
'is abused' is the definition.
(similar in meaning)
'wickedness in a revolutionary' is the wordplay.
'wickedness' becomes 'evil' (synonyms).
'in' is an insertion indicator.
'a revolutionary' becomes 'red' (red can informally mean communist).
'evil' placed into 'red' is 'REVILED'.
(Other definitions for reviled that I've seen before include "Deliver (anag.)" , "Abusively criticised" , "Maligned, vilified" , "Abused" .)