Carry drink left on board (7)
I believe the answer is:
support
'carry' is the definition.
(thesaurus)
'drink left on board' is the wordplay.
'drink' becomes 'sup' (I've seen this before**).
'left on board' becomes 'port' (port is left on board a ship).
'sup'+'port'='SUPPORT'
(Other definitions for support that I've seen before include "Bear the weight of (something)" , "used to give strength?" , "Bear; assistance" , "Keep from falling, as crutch does (7)" , "Encourage - endorse" .)