Quick police operation featuring Robocop finally (5)
I believe the answer is:
rapid
'quick' is the definition.
(synonyms)
'police operation featuring robocop finally' is the wordplay.
'police operation' becomes 'raid' (I've seen this in another clue).
'featuring' is an insertion indicator.
'finally' indicates one should take the final letters.
The last letter of 'robocop' is 'p'.
'raid' placed around 'p' is 'RAPID'.
(Other definitions for rapid that I've seen before include "Moving at speed" , "Prompt" , "Quickly accomplished" , "Happening at great speed" , "Precipitate" .)