Sack left in current (5)
I believe the answer is:
rifle
'sack' is the definition.
(both can mean to steal)
'left in current' is the wordplay.
'left' becomes 'l' (common abbreviation).
'in' indicates putting letters inside.
'current' becomes 'rife' (similar in meaning).
'l' going within 'rife' is 'RIFLE'.
(Other definitions for rifle that I've seen before include "lock, stock and barrel" , "Steal and carry off - firearm" , "Sack; firearm" , "Plunder - ransack" , "shoot?" .)