Fantastic police officer (5)
I believe the answer is:
super
This clue is a double definition.
'fantastic' is the first definition.
(I've seen this before)
'police officer' is the second definition.
(term for a senior police officer)
(Other definitions for super that I've seen before include "Prefix meaning over-excellent!" , "Informally excellent, terrific" , "Fantastic" , "Smashing, terrific" , "Spiffing!" .)