atama no neji ga hazurete iru lit. ‘the screw in your head has come off’
Japanese idiom, casual. Someone is a bit crazy, or is acting as if they’ve lost their mind.
How do people use 頭のネジが外れている
?
Casual and a bit rude, said among friends about someone whose ideas or behaviour seem unhinged: “あいつ、頭のネジが外れてるよ”. In speech the い of いる usually drops (外れてる). People also say the screw has “flown off” (飛んでいる), which is the form Tatoeba has.
Also said 頭のネジが飛んでいる
頭のネジが外れている
in real sentences
-
トムは頭のネジが飛んでいる。
Tomu wa atama no neji ga tonde iru.
Tom is crazy.
Tatoeba, sentence by OrangeTart, translation by CK, CC BY 2.0 FR
Where does 頭のネジが外れている
come from?
No source traces it. ネジ in the sense of a screw is recorded in Hepburn’s Japanese-English dictionary of 1867 (Nihon Kokugo Daijiten via Kotobank), so the idiom can’t be older than that. English has the same picture (Wiktionary quotes “have a screw loose” from Trollope in the 1870s) and so does German, which makes a borrowing possible, but that’s a guess.
Mistakes learners make with 頭のネジが外れている
Using it as a neutral description of someone with a mental illness. It’s a joking insult for wild or reckless behaviour, and aimed at a real condition it sounds cruel.
Other Japanese idioms like 頭のネジが外れている
Spot a mistake in 頭のネジが外れている
?
Send a correction, or a sentence you’d actually say with it. Everything is read before anything on this page changes.