Generous with French wine during a performance (6)
I believe the answer is:
giving
'generous' is the definition.
(similar in meaning)
'french wine during a performance' is the wordplay.
'french wine' becomes 'vin' ('wine' in French).
'during' means one lot of letters goes inside another.
'a performance' becomes 'gig' (I've seen this in other clues).
'vin' inserted inside 'gig' is 'GIVING'.
'with' acts as a link.
(Other definitions for giving that I've seen before include "Donating" , "Granting" , "'Friday's child is loving and . . . . . .'" , "Yielding; presenting" , "Handing over" .)