Upfront amount (4)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">upfront amount</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ante that I've seen before include "early payment" , "Stake, bet" , "not post" , "Initial contribution to the common pot" , "Money for poker" .)