noun
lost game; game with slim chances of winning
Refers to a match or contest that has already been lost, or one that is almost certainly going to be lost. Often used in sports and competitive contexts.
あの試合は完全に負け試合だった。
That game was a complete lost cause.
負け試合でも最後まで諦めない。
Even in a losing game, I won't give up until the end.
Similar meaning but more literary or historical, often used for battles or wars.
Compound of 負け (make, 'losing') + 試合 (shiai, 'match, game').