Game ending (4)
I believe the answer is:
mate
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">game ending</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 mate that I've seen before include "declared winning position on board" , "Pal, chum" , "Friend; chess move" , "Fellow worker" , "Move terminal for King" .)