n.

1. 正当的报应
2. 给以报应者；复仇者
3. 必然使计划失败的人，劲敌；无可避免的后果
   For the last thirty years, he has been my nemesis.

   在过去三十年来，他一直是我的劲敌。

n.

1. the inescapable agent of someone's downfall, especially when deserved.
   ▸a downfall caused by an inescapable agent.
2. chiefly N. Amer. a long-standing or persistent rival or enemy.