Outlaw cop brought back (3)
I believe the answer is:
ban
'outlaw' is the definition.
(banning is a kind of outlawing)
'cop brought back' is the wordplay.
'cop' becomes 'nab' (synonyms).
'brought back' is a reversal indicator.
'nab' back-to-front is 'BAN'.
(Other definitions for ban that I've seen before include "Censor or proscribe" , "outlaw" , "the calling of young vassals" , "'Forbid, prohibit (3)'" , "Embargo" .)