Large bag; plunder (4)
I believe the answer is:
sack
I believe this is a double definition.
'large bag' is the first definition.
(I've seen this before)
'plunder' is the second definition.
(I know that plunder can be written as sack)
(Other definitions for sack that I've seen before include "Loot the large bag" , "boot" , "Plundering by a mob" , "Big, coarse bag" , "Container for coal etc" .)