失效

1. lose efficacy; lose effectiveness; cease to be effective

♦ 这药已~了。 The medicine no longer has any effect.

♦ 使水雷~ deactivate mines

2. (of a treaty, an agreement, etc.) be no longer in force; become invalid

♦ 自动~ automatically cease to be in force

♦ 条约的~ voidance (or voidness) of a treaty