Smart pop star (5)
I believe the answer is:
sting
I believe this clue is a double definition.
'smart' is the first definition.
(both can mean to burn or hurt)
'pop star' is the second definition.
(front-man of The Police)
(Other definitions for sting that I've seen before include "Hurt; smart" , "Bee/wasp wound" , "Sharp tingling pain" , "Painful wound - confidence trick" , "Undercover operation; wound" .)