[shī xiào]
(失去效力) lose efficacy; lose effectiveness; cease to be effective
The medicine no longer has any effect.
这药已失效了。
(无效) (of a treaty, an agreement, etc.) be no longer in force; become invalid
voidance; voidness of treaties
条约的失效
an invalid cheque
一张失效的支票
automatically cease to be in force
自动失效
This certificate is invalid.
这张证明已失效。