Lighter game (7)
I believe the answer is:
pontoon
This clue is a double definition.
'lighter' is the first definition.
(I know that pontoon is a type of lighter)
'game' is the second definition.
(I've seen this before)
(Other definitions for pontoon that I've seen before include "Card game - type of bridge" , "Card game; floating support" , "Bridge of boats" , "Half of 1D [GAME OR BIRD]" , "Lighter" .)