Perhaps go up for it (4)
I believe the answer is:
game
I believe this is a double definition.
'perhaps go' is the first definition.
(go is an example of a game)
'up for it' is the second definition.
(both can mean enthusiastic or keen)
(Other definitions for game that I've seen before include "Final declaration of tennis result - . . . ., set and match" , "For instance, go" , "Food from wild animals" , "Something to play or to chase" , "Sport - amusement" .)