Blunder and drink without team (5,2)
I believe the answer is:
screw up
'blunder' is the definition.
(synonyms)
'drink without team' is the wordplay.
'drink' becomes 'sup' (to sup is to drink).
'without' is an insertion indicator ('without' can be similar in meaning to 'outside').
'team' becomes 'crew' (crew is a kind of team).
'sup' going around 'crew' is 'SCREW-UP'.
'and' is the link.
(Other definitions for screw up that I've seen before include "Get it badly wrong" , "Completely mismanage a situation" , "put cap on?" , "Go badly wrong" , "Fail badly" .)