dead letter

noun

1

: something that has lost its force or authority without being formally abolished

As a result of such loopholes, the statute became a dead letter.

—William M. McGovern, Jr. et al.

2

: a letter that is undeliverable and unreturnable by the post office

Examples of dead letter in a Sentence

Recent Examples on the Web

The 2015 deal has become a dead letter, but its nominal expiration date of October 18 coincides with the Trump administration’s new opportunity to pull in its EU partners to create a solid Western position that would put more international pressure on Iran’s highly stressed leadership. —John R. Bolton, The Atlantic, 9 July 2025

Trump wants the war to end, but Ukraine will not enjoy lasting peace without guarantees against further Russian aggression, and our allies know that any security guarantee without the U.S. will be a dead letter. —Ian Kelly, Chicago Tribune, 21 Feb. 2025

The note makes its way to the desk of Jasper, a seasoned ‘dead letter’ investigator at a 1980s midwestern post office. —Matt Grobar, Deadline, 13 Feb. 2025

Today, to our peril, the Monroe Doctrine is becoming a dead letter. —Steve Forbes, Forbes, 24 Sep. 2024

Word History

First Known Use

1663, in the meaning defined at sense 1

Rhymes for dead letter

• abettor
• newsletter
• typesetter
• better
• bettor
• debtor
• fetter
• getter
• netter
• petar
• petter
• rhetor

Kids Definition

dead letter

noun

1

: something that has lost its force or authority without being abolished

2

: a letter that cannot be delivered or returned by the post office