dead letter noun
plural dead letters
plural dead letters
Learner's definition of DEAD LETTER
[count]
1
: a letter that cannot be delivered or returned by the post office because of an incorrect address or other problem死信;无法投递(或退回)的信
2
: a law or agreement that has lost its force or authority无人遵守的法律;形同虚设的规定;空文 —
usually singular通常用单数