Feed the kitty (4)
I believe the answer is:
ante
'feed the kitty' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ante that I've seen before include "Pay" , "'Behind, before (4)'" , "Stake (that may be upped?)" , "Stake put up by a poker-player before receiving cards" , "Initial bet" .)