Of a situation in which there is a net loss(adjective)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "negative-sum" in a sentence
"In international relations, you are frequently looking at avoiding war – always a negative-sum game in the short run and frequently in the long."
"But the many attempts at communism have shown that some economic systems are negative-sum games."
"Business leaders seem unaware of the critical difference between the market world of positive-sum transactions and the political world of negative-sum transactions."