Awful lot of money on game (9)
I believe the answer is:
badminton
'game' is the definition.
(badminton is a kind of game)
'awful lot of money on' is the wordplay.
'awful' becomes 'bad' (similar in meaning).
'lot of money' becomes 'mint' (I've seen this before).
'bad'+'mint'+'on'='BADMINTON'
(Other definitions for badminton that I've seen before include "One sport" , "22 Across sport" , "Game played with a shuttlecock" , "Seat of the Duke of Beaufort - racket game" , "Racquet sport" .)