Managed large bag for plunder (7)
I believe the answer is:
ransack
'plunder' is the definition.
('ransack' can be a synonym of 'plunder')
'managed large bag' is the wordplay.
'managed' becomes 'ran' (I've seen this before).
'large bag' becomes 'sack' (I've seen this before).
'ran'+'sack'='RANSACK'
'for' acts as a link.
(Other definitions for ransack that I've seen before include "Examine thoroughly" , "Pillage, plunder" , "Search thoroughly and roughly" , "Search thoroughly and destructively" , "Plunder or turn upside down in search" .)