dead letter

noun
1.
a law, ordinance, etc., that has lost its force but has not been formally repealed or abolished.
2.
a letter that cannot reach the addressee or be returned to the sender, usually because of incorrect address, and that is sent to and handled in a special division or department (dead-letter office) of a general post office.
Origin
1570-80
Related forms
dead-letter, adjective
Examples from the web for dead letter
  • If it does not have a return address, it will be returned to the post office dead letter file.
  • Gradually the pendulum moved to the other extreme, and the common law of trade restraint became largely a dead letter.
  • Warrant unaccompanied by a duly signed rate bill a dead letter.
British Dictionary definitions for dead letter

dead letter

noun
1.
a letter that cannot be delivered or returned because it lacks adequate directions
2.
a law or ordinance that is no longer enforced but has not been formally repealed
3.
(informal) anything considered no longer worthy of consideration
Slang definitions & phrases for dead letter

dead letter

noun phrase

A matter no longer of concern or currency; a bygone issue (1663+)


Idioms and Phrases with dead letter

dead letter

.
An unclaimed or undelivered letter that is eventually destroyed or returned to the sender. For example, She moved without leaving a forwarding address, so her mail ended up in the dead letter office. [ c. 1700 ]
.
A statute or directive that is still valid but in practice is not enforced. For example, The blue laws here are a dead letter; all the stores open on Sundays and holidays. [ Second half of 1600s ]