adversarial
adjective formal uk/ˌæd.vəˈseə.ri.əl/ us/ˌæd.vɚˈser.i.əl/
对立的;对抗的;敌对的
involving people opposing or disagreeing with each other
In the old days of two-party adversarial politics, voting was easy. 在过去两党对抗的政治环境中，决定投谁的票并不困难。