dead letter
noun /ˌded ˈletə(r)/
/ˌded ˈletər/
- [usually singular] a law or an agreement that still exists but that is ignored
无人遵守的法律;形同虚设的协定;空文 - The treaty had been a dead letter for many years.
该条约多年来一直是一纸空文。
- The treaty had been a dead letter for many years.
- (especially North American English) a letter that cannot be delivered to an address or to the person who sent it
死信;无法投递(或退回)的邮件