Find fault with swallowing wife's hock (4)
I believe the answer is:
pawn
'hock' is the definition.
(I know that hock can be written as pawn)
'find fault with swallowing wife's' is the wordplay.
'find fault with' becomes 'pan' (to pan something is to criticise it heavily).
'swallowing' indicates putting letters inside.
'wife' becomes 'w' (abbreviation).
'pan' placed around 'w' is 'PAWN'.
(Other definitions for pawn that I've seen before include "Stooge; hock" , "Chesspiece" , "Deposit as pledge" , "Exploited person" , "One getting used" .)