名詞 insanity:

1. relatively permanent disorder of the mind

1. Genius is but one remove from insanity.
   天才興瘋狂之間只有毫厘之差。

in.san.i.ty

n.（名詞）
【復(fù)數(shù)】 in.san.i.ties
Persistent mental disorder or derangement.
精神病：持續(xù)的精神紊亂或錯亂
Law
【法律】
Unsoundness of mind sufficient in the judgment of a civil court to render a person unfit to maintain a contractual or other legal relationship or to warrant commitment to a mental health facility.
精神失常：為民事法庭所判定的心智不健全狀態(tài)，處于此狀態(tài)下的個人被認(rèn)為不適于維持合同或其他法律關(guān)系或應(yīng)送交精神健康機(jī)構(gòu)
In most criminal jurisdictions, a degree of mental malfunctioning sufficient to relieve the accused of legal responsibility for the act committed.
精神失常：在大部分刑事審判中，可以解除被告所犯罪行的法律責(zé)任的精神失常的程度

Extreme foolishness; folly.
愚蠢：極端的愚蠢；愚蠢
Something that is extremely foolish.
特別愚蠢的事物

<參考詞匯><同義詞>insanity,lunacy,madness,mania,dementiaThese nouns denote conditions of serious mental disability.
這些名詞表示嚴(yán)重精神失常的狀況。
Insanity is a grave, often prolonged condition of mental disorderthat prevents a person from being held legally responsible for his or her actions:
Insanity 是一種嚴(yán)重的，通常是延續(xù)的精神紊亂的狀態(tài)，它使某人可不對他或她的行為負(fù)法律責(zé)任：
例句：
was judged not guilty for reasons of insanity.
由于精神失常而被判無罪。

Lunacy often denotes derangement relieved intermittently by periods of clear-mindedness:
Lunacy 是指伴隨著間歇的精神正常的精神錯亂：
例句：
tried to jump out of the fortieth-floor window in a moment of utter lunacy.
在突發(fā)的精神失常中試圖從四樓的窗戶跳出去。

Madness, a more general term, often stresses the violent aspect of mental illness:
Madness 是一個更為通用的詞，通常強(qiáng)調(diào)精神病的狂暴的一面：
例句：
delusions that progressed to a form of madness.
發(fā)展成為一種瘋狂狀態(tài)的幻覺。

Mania refers principally to the excited phase of manic-depressive psychosis:
Mania 主要指躁狂抑郁精神病的狂躁的一面：
例句：
prescribed drugs to control the patient`s periods of mania.
開藥方來控制病人的躁狂的階段。

Dementia implies mental deterioration brought on by organic brain disorder:
Dementia 暗指腦組織破壞而引致的精神惡化：
例句：
underwent progressive stages of dementia.
經(jīng)歷了精神失常由輕到重的發(fā)展階段