Spoils wife impressed by sink (4)
I believe the answer is:
swag
'spoils' is the definition.
(I've seen this before)
'wife impressed by sink' is the wordplay.
'wife' becomes 'w'.
'impressed by' is an insertion indicator.
'sink' becomes 'sag' (sagging is a kind of sinking).
'w' going into 'sag' is 'SWAG'.
(Other definitions for swag that I've seen before include "pack of Aussie travellers" , "Burglar's plunder" , "Ill-gotten gains" , "Stolen goods" , "Burglar's haul" .)