Wine given to one performing part (7)
I believe the answer is:
portion
'part' is the definition.
(I know that part can be written as portion)
'wine given to one performing' is the wordplay.
'wine' becomes 'port' (port is a kind of wine).
'given to' is a charade indicator (letters next to each other).
'one' becomes 'i' (Roman numeral).
'performing' becomes 'on' (as in being on stage).
'port'+'i'+'on'='PORTION'
(Other definitions for portion that I've seen before include "A lot of" , "Serving" , "Segment" , "Helping - fate" , "Part of a whole" .)