Fancy little drink with model (7)
I believe the answer is:
suppose
'fancy' is the definition.
(both can mean to guess or suspect)
'little drink with model' is the wordplay.
'little drink' becomes 'sup' (sup can mean a small drink).
'with' means one lot of letters go next to another.
'model' becomes 'pose' (model can mean to pose).
'sup'+'pose'='SUPPOSE'
(Other definitions for suppose that I've seen before include "Presume" , "Fancy" , "'Believe, perhaps on uncertain grounds (7)'" , "Think, assume" , "Picture" .)