Ace! It's flipping fizzy wine! (4)
I believe the answer is:
asti
'fizzy wine' is the definition.
(I've seen this before)
'ace it's flipping' is the wordplay.
'ace' becomes 'a' (abbreviation).
'flipping' indicates anagramming the letters (I've seen 'flips' mean this).
'its' anagrammed gives 'sti'.
'a'+'sti'='ASTI'
(Other definitions for asti that I've seen before include "Alcohol" , "Italian product" , "Capital of a north-west Italian province, known for its sparking wine" , "Source of fizz" , "Italian 'sparkler'" .)