Measure of liquid bridge-player put in large vessel (7)
I believe the answer is:
galleon
'large vessel' is the definition.
(I've seen this before)
'measure of liquid bridge-player put in' is the wordplay.
'measure of liquid' becomes 'gallon'.
'bridge player' becomes 'e' (bridge players are North, East, South, West).
'put in' means one lot of letters goes inside another.
'gallon' enclosing 'e' is 'GALLEON'.
(Other definitions for galleon that I've seen before include "Old Spanish war-ship" , "One might sink" , "Old Spanish ship" , "All gone (anag.)" , "Large old square-rigged sailing ship" .)