End of a chess game (4)
I believe the answer is:
mate
'end of a chess game' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for mate that I've seen before include "Ship's officer or marital partner" , "Fellow member, partner" , "declared winning position on board" , "Spouse on team" , "Marry - friend" .)