Willing to play (4)
I believe the answer is:
game
This clue is a double definition.
'willing' is the first definition.
(game can mean willing to do something)
'play' is the second definition.
(I know that game is a more specific form of the action play)
'to' is the link.
(Other definitions for game that I've seen before include "Sport - amusement" , "Birds hunted for food" , "Something to play or to chase" , "Final declaration of tennis result - . . . ., set and match" , "Willing; plucky" .)