Hidden shooter (6)
I believe the answer is:
sniper
'hidden shooter' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sniper that I've seen before include "one who takes pot from a safe place" , "He shoots form cover" , "He shoots from hiding-place" , "One aiming" , "One shoots from a concealed place" .)