White pawn (4)
I believe the answer is:
hock
I believe this is a double definition.
'white' is the first definition.
(type of white wine)
'pawn' is the second definition.
(hock can mean to pawn an item at a pawnbroker's)
(Other definitions for hock that I've seen before include "Hamstring" , "Leg joint on horse e.g." , "Uncle's pledge" , "Dry white wine" , "White wine and horse's joint" .)