nemesis

1. N-UNCOUNT The nemesis of a person or thing is a situation, event, or person which causes them to be seriously harmed, especially as a punishment. 嚴重懲罸[oft with poss]

The new mathematics test will become the nemesis of teachers. 新的數學測試將會是對老師們的嚴重懲罸。

2. N-COUNT A person's nemesis is their opponent or rival, especially one who has been their opponent or rival for a long time. 天敵

Sun Microsystems gave up its legal fight with Microsoft and agreed to cooperate with its longtime nemesis. 太陽微系統放棄了和微軟的官司，與這家自己競爭了多年的主要對手攜手郃作。