Vessel holding first of wine, hock (4)
I believe the answer is:
pawn
'hock' is the definition.
(I know that hock can be written as pawn)
'vessel holding first of wine' is the wordplay.
'vessel' becomes 'pan' (vessel or container for cooking).
'holding' is an insertion indicator.
'first of wine' becomes 'w' (1st letter of 'wine').
'pan' placed around 'w' is 'PAWN'.
(Other definitions for pawn that I've seen before include "Person used to gain an end" , "Lodge (item) for money" , "Insignificant player" , "instrument" , "Minor chessman" .)