Stake needed, unlimited (4)
I believe the answer is:
ante
'stake' is the definition.
(stake in poker)
'needed unlimited' is the wordplay.
'needed' becomes 'wanted' ('want' can be a synonym of 'need').
'unlimited' means to look at the middle letters (remove the limits/outer letters).
The centre of 'wanted' is 'ANTE'.
(Other definitions for ante that I've seen before include "Preceding birth" , "Hoofed mammal" , "advance payment" , "Prefix meaning before" , "not post" .)