Willing prey (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)
'prey' is the second definition.
(game is a kind of prey)
(Other definitions for game that I've seen before include "Competitive activity with rules" , "meat from hunting" , "Willing to try" , "Willing; recreation" , "Eager and willing to accept challenge" .)