Turn down drink (5,4)
I believe the answer is:
knock back
This clue is a double definition.
'turn down' is the first definition.
(both can mean to reject)
'drink' is the second definition.
(thesaurus)
(Other definitions for knock back that I've seen before include "finish off drink quickly" , "Refuse" , "Refusal" , "Disappointing rejection" , "Turn down - drink" .)