How to say "madness" in Japanese

Choosing the right word

狂気きょうきCommon
no-adjectiveThe neutral word for madness or insanity as a state of mind. This is usually the word you want when describing someone's mental derangement or the madness of an idea or act.
それをやってみるなんて狂気きょうきに近ちかい。↗
It is little short of lunacy to try it.
キチガイCommon
nounA derogatory word meaning madman or lunatic; as 'madness' it carries strong contempt. This is a sensitive slur, seldom the word you want — avoid it in ordinary speech and writing.
デルバートは気違きちがいだと思おもうよ。↗
I think that Delbert is crazy.
狂乱きょうらんCommon
suru verb, intransitive verb, no-adjectiveFury or frenzy rather than insanity: wild, agitated excitement. Choose this when 'madness' means frantic or furious behavior, not a mental condition.

Use 狂気 for the neutral state of madness or insanity, 狂乱 for wild frenzy or furious agitation, and avoid 「キチガイ」, a derogatory slur for a madman.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

Japanese equivalents

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