Translation guide
The English phrase "dead letter" has two main meanings: a law or rule that is no longer enforced, and an undeliverable piece of mail. This guide covers both, with natural Japanese equivalents.
Describing a law, regulation, or rule that officially exists but is not enforced or observed in practice.
Literally 'dead sentence', this is the most direct equivalent for a law or regulation that has become a dead letter. Commonly used in legal and political contexts.
その法律はもはや死文化している。
That law has become a dead letter.
Referring to a piece of mail that cannot be delivered to the addressee and cannot be returned to the sender.
The standard postal term for undeliverable mail. Used by Japan Post and in official contexts.
不達郵便は一定期間保管された後、処分されます。
Dead letters are held for a certain period and then disposed of.
Do not translate "dead letter" literally as 死んだ手紙 (shinda tegami). This is not used in Japanese and would cause confusion.
死文 is a noun meaning 'dead letter' (law). 空文化する is a verb phrase meaning 'to become a dead letter'. Use 死文化する for the same verbal meaning.
Means 'a law that has become an empty shell'. Emphasizes that the law exists only on paper.
この規制は空文化している。
This regulation has become a dead letter.
Used for rules or regulations that have become mere formalities, without substance. '形骸化' means 'becoming a mere shell'.
その規則は完全に形骸化している。
That rule has become a complete dead letter.
A set phrase meaning 'a law in name only'. Stronger and more literary than 死文.
それは有名無実の法律だ。
It's a dead letter law.
Literally 'mail with unknown address'. A descriptive phrase that is easily understood in everyday conversation.
宛先不明の郵便物が戻ってきた。
The dead letter came back because the address was unknown.
Means 'mail that cannot be returned'. Used in postal operations when both delivery and return are impossible.
返送不能郵便は死信として扱われる。
Undeliverable and unreturnable mail is treated as dead letters.