Wine, some infanta's tipple (4)
I believe the answer is:
asti
'wine' is the definition.
(I've seen this before)
'some infanta's tipple' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'ASTI' is hidden within 'infantas tipple'.
(Other definitions for asti that I've seen before include "18" , "Piedmontese white wine" , "Fizzy wine" , "Italian white wine" , "Capital of a north-west Italian province, known for its sparking wine" .)