Translation guide
Describing someone as an 'insane person' in Japanese requires careful word choice, as direct translations can sound harsh, clinical, or outdated. The best option depends on context: casual exaggeration, medical/legal settings, or literary descriptions.
To call someone crazy, insane, or out of their mind in a casual, often hyperbolic way, similar to English 'You're insane!' or 'He's a madman.'
Literally 'mad person' or 'lunatic'. Strong and direct, but can be used in casual exaggeration among friends or in fiction. Not typically used in polite conversation.
That guy is insane.
Doing something like that, are you insane?
Slangy way to say 'crazy person' or 'nutcase'. 'イカれる' means 'to be crazy/broken'. Very casual and often used in a joking or derogatory way.
That crazy person is saying weird stuff again.
Extremely offensive slur for a crazy person. Historically used but now considered discriminatory hate speech. Avoid using this word; it is included here only for recognition.
Highly offensive. Do not use. Equivalent to the most severe English slurs for mentally ill people.
He screamed like a madman.
To refer to a person with a severe mental illness in a clinical or formal context.
Official term for 'person with a mental disorder'. Neutral and appropriate in medical, legal, or social welfare contexts.
I will explain the support system for persons with mental disorders.
Specifically 'mental patient' or 'psychiatric patient'. Used in hospital settings. Can sound somewhat dated or clinical.
To describe a person as mad, insane, or deranged in a narrative or dramatic style.
Also used in literary or historical contexts to mean 'madman' or 'lunatic'. Can appear in titles or dramatic dialogue.
He laughed like a madman.
Kanji form of the slur; sometimes seen in older literature. Now considered highly offensive. Use only when discussing historical texts.
Offensive in modern usage. Avoid unless quoting historical sources.
Calling someone 'insane' directly in Japanese can be much more offensive than in English. In most situations, it's better to describe the behavior rather than label the person. For example, instead of 'He is insane,' say 'He is acting strangely' (彼は変な行動をしている).
狂人 (kyōjin) is a strong, often derogatory term for a mad person, while 精神障害者 (seishin shōgaisha) is the neutral, official term for a person with a mental disability. Use 狂人 only in casual, fictional, or historical contexts, and 精神障害者 in formal or respectful discussions.
He is hospitalized as a psychiatric patient.
The word 'kichigai' is used in that novel.