Gun used by those who plunder? (5)
I believe the answer is:
rifle
This clue could be a double definition.
'gun used by those who' is the first definition.
'rifle' can be an answer for 'gun' (rifle is a kind of gun). I am not certain of the rest of the definition.
'plunder?' is the second definition.
(I know that despoil can be written as rifle)
Can you help me to learn more?
(Other definitions for rifle that I've seen before include "Security provider with stock" , "Shoulder firearm" , "shoot?" , "Weapon - sack" , "Pillage; a weapon" .)