adversary

The grandmaster studied his adversary's previous chess games for hours.

(Chinese) 这位象棋大师花了几个小时研究对手以前的棋局。

He showed great respect for his political adversary during the national debate.

(Chinese) 在国家辩论中，他对他的政治对手表现出了极大的尊重。

Our legal system is based on an adversary process where two sides present their evidence to a judge.

(Chinese) 我们的法律系统基于对抗性程序，双方在法官面前出示各自的证据。

The negotiations became adversary when both companies refused to compromise on price.

(Chinese) 当两家公司都拒绝在价格上妥协时，谈判变得具有对抗性。