Character getting Joe upset during a card game (6)
I believe the answer is:
figaro
'character' is the definition.
(I have seen 'Operatic character ' mean 'figaro' so perhaps 'character' could also mean 'figaro')
'joe upset during a card game' is the wordplay.
'joe' becomes 'GI' (GI Joe).
'upset' shows that the letters should be reversed in order.
'during' is an insertion indicator.
'a card game' becomes 'faro' (faro is a kind of card game).
'gi' back-to-front is 'ig'.
'ig' placed inside 'faro' is 'FIGARO'.
'getting' acts as a link.
(Other definitions for figaro that I've seen before include "Operatic character" , "Le -, French paper" , "The Barber of Seville" , "Mozart's 'Marriage'" , "Mozart tells of his operatic marriage" .)