1.
dead word; obsolete expression
A word or expression that was once commonly used but is no longer current. Often said humorously about slang or trends that have fallen out of fashion.
その言葉はもう死語だよ。
That word is already obsolete.
「ナウい」は完全に死語になった。
"Naui" (trendy) has become completely obsolete.
若者の流行語はすぐに死語になりやすい。
Youth slang tends to become obsolete quickly.
2.
dead language
A language that is no longer spoken as a native language by any community, such as Latin or Ancient Greek.
ラテン語は死語だ。
Latin is a dead language.
死語とされる言語でも研究者には重要だ。
Even languages considered dead are important to researchers.
死語を復活させようとする運動もある。
There are also movements trying to revive dead languages.
USAGE:
Sense 1 is the more common usage in everyday Japanese. Often used humorously when someone uses an outdated slang term or expression. Japanese has many generational slang words that quickly become 死語, such as ナウい (1980s slang for "trendy").
COMMON COLLOCATIONS:
- 死語になる (to become obsolete)
- 死語と化す (to turn into a dead word)
- もはや死語 (already a dead word)
SIMILAR WORDS:
- 廃語: obsolete word — more technical, linguistic term
- 古語: archaic word — specifically refers to words from classical Japanese