Assume drink leads to attitude (7)
I believe the answer is:
suppose
'assume' is the definition.
(thesaurus)
'drink leads to attitude' is the wordplay.
'drink' becomes 'sup' (I've seen this before).
'leads' is a charade indicator (letters next to each other).
'to attitude' becomes 'pose' (I've seen this before).
'sup'+'pose'='SUPPOSE'
(Other definitions for suppose that I've seen before include "Assume, imagine" , "'Believe, perhaps on uncertain grounds (7)'" , "Picture" , "Judge" , "Put forward - imagine" .)