Fizzy wine (4)
I believe the answer is:
asti
'fizzy wine' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for asti that I've seen before include "Piedmont wine city, SE of Turin" , "Italian drunk" , "Italian town producing sparkling wine" , "Italian town, famous for its wine" , "Italian wine - (then change a letter for ...)" .)