It's a new drink (4)
I believe the answer is:
asti
'drink' is the definition.
(Asti is a type of wine)
'it's a new' is the wordplay.
'new' indicates anagramming the letters.
'its'+'a'='itsa'
'itsa' anagrammed gives 'ASTI'.
(Other definitions for asti that I've seen before include "Italian wine - (then change a letter for ...)" , "Italian 'sparkler'" , "Capital of a north-west Italian province, known for its sparking wine" , "Piedmont wine city, SE of Turin" , "Piedmontese white wine" .)