Put money (on) (3)
I believe the answer is:
bet
'put money on' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bet that I've seen before include "Wager, gamble" , "Wager, back" , "Speculation" , "Wager, speculate" , "'Stake, wager (3)'" .)