If you refer to a situation as a zero-sum game, you mean that if one person gains an advantage from it, someone else involved must suffer an equivalent disadvantage. They believe they're playing a zero-sum game, where both must compete for the same paltry resources. A situation in which a gain by one person or side must be matched by a loss by another person or side: "It's not a zero-sum game in which either youth or pensioners must lose" (Earl W. Foell). a situation in which you receive as much money or advantages as you give away