Coin for police officer (6)
I believe the answer is:
copper
I believe this is a triple definition!
'coin' is the first definition.
(copper is a kind of coin)
'for police' is the second definition.
(thesaurus)
'officer' is the third definition.
(I know that officer can be written as copper)
(Other definitions for copper that I've seen before include "PC" , "Reddish-brown metallic element" , "English policeman" , "Coin, policeman or metallic element" , "Metal, Cu" .)