Bag for plunder? (4)
I believe the answer is:
sack
This clue is a double definition.
'bag' is the first definition.
(sack is a kind of bag)
'plunder?' is the second definition.
('sack' can be a synonym of 'plunder')
'for' is the link.
(Other definitions for sack that I've seen before include "present holder" , "Plundering by a mob" , "Large bag; dismiss" , "Receptacle" , "Plunder; wine; bag" .)