Two-deck game (7)
I believe the answer is:
canasta
'two-deck game' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for canasta that I've seen before include "Card game at a scan" , "Card-game, a form of rummy" , "Card game -- as an act (anag)" , "Rummy-like card-game" , "Card-game played with two packs of cards" .)