from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. Mental illness or derangement. No longer in scientific use.
  • n. Law 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.
  • n. Law In most criminal jurisdictions, a degree of mental malfunctioning sufficient to relieve the accused of legal responsibility for the act committed.
  • n. Extreme foolishness; folly.
  • n. Something that is extremely foolish.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The state of being insane; madness.

from the GNU version of the Collaborative International Dictionary of English

  • n. The state of being insane; unsoundness or derangement of mind; madness; lunacy.
  • n. Such a mental condition, as, either from the existence of delusions, or from incapacity to distinguish between right and wrong, with regard to any matter under action, does away with individual responsibility.

from The Century Dictionary and Cyclopedia

  • n. A seriously impaired condition of the mental functions, involving the intellect, emotions, or will, or one or more of these faculties, exclusive of temporary states produced by and accompanying acute intoxications or acute febrile diseases.
  • n. In its legal use, insanity consists in the lack of such mental soundness as renders a person criminally responsible, or capable of making a valid contract, conveyance, or will, or of managing his own affairs. There is great difference of opinion as to what extent of disease or imperfect development, and what, if any, aberrations of mind not traceable to disease or imperfection of the brain, should be regarded as constituting this degree of mental unsoundness. The tendency of legal opinion has long been to enlarge the scope of the word, and extend the rules as to insanity to derangements not recognized in earlier times, when insane was used as the equivalent of mad or lunatic, and insanity generally implied furor or mania, or, at least, obvious forms of total defect of responsible understanding. What constitutes legal insanity—that is, exonerative or incapacitating insanity—in doubtful cases is now universally regarded as depending upon the relation between the defect in the particular mind and the nature of the act in question. Thus, insanity, as a defense in criminal law, means, according to the rule in England and in many of the United States, incapacity to distinguish between right and wrong, in respect to the act in question, or incapacity to be conscious of acting contrary to law; while by some authorities inability to control the will (irresistible morbid impulse) also is recognized as insanity. Insanity in reference to the law of contracts is generally understood to mean such a defect as incapacitates from a rational assent, considering the nature of the contract, whether marriage, partnership, sale, etc. Insanity (or, as more commonly expressed, unsoundness of mind) in reference to the law of wills is generally understood to mean such a defect as incapacitates from knowing or collecting in mind the facts respecting the property to be disposed of and the persons naturally and justly to be considered in its disposal, or from making an intelligent and rational choice as to its disposal. It has often been defined too narrowly, as consisting only in delusion. It is a disputed question whether the existence of disease or defect in the brain itself is an essential fact. Some of those who hold that one or the other always characterizes insanity are understood to assert that the disease or defect may be inferred from the irrationality of conduct, without other independently adequate evidence.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. relatively permanent disorder of the mind


from Wiktionary, Creative Commons Attribution/Share-Alike License

A three-part word (root 'sane', prefix 'in-' meaning 'not', suffix '-ity', meaning 'the state of'). Derived from Latin precursory equivalents. Two possible candidates for construction order:


  • Dr Jones was also frankly appalled by the use of the term insanity with regard to the king as the label was enough to destroy a mans credit and happiness for ever.


  • Our view is that we've been trying to get the market to solve cybersecurity for years, and we don't want to repeat the definition of insanity, which is continuing to do the same thing over and over again and expecting a different outcome.

    The Cop on the Cyber Beat

  • But their efforts to address the looming long-term care financial problem should not be associated with the word "insanity," nor should the forthright efforts of Health and Human Services Secretary Kathleen Sebelius, who has held to her commitment not to foist an unsustainable program on future American taxpayers.

    Class Is Dead but Problem Remains

  • But the definition of legal insanity, ladies and gentlemen, is very different than what we typically think of when we think of the word insanity.


  • The quickest way to insanity is to keep voting republican and expect different results ....

    Reid stands by Lieberman despite Obama attack

  • And secondly that what she called the insanity of the family holiday was good for keeping politicians sane.

    The Economist: Daily news and views

  • What was that old saying, "insanity is doing the same thing over and over and expecting different results"

    GOP chairman isn't sure who his insurance provider is

  • The definition of insanity is trying the same thing over and over and expecting a different result.

    Lugar: U.S. should talk with Iran

  • What was really perverse about the recent period of insanity is that the incentives were aligned in such a way that mortgage brokers NO LONGER GAVE A DAMN whether the lenders would be paid back, and all too many borrowers were a little too willing to be told what they wanted to hear without realizing such a shift in incentives had taken place.

    Matthew Yglesias » On So-Called “Irresponsible” Borrowers

  • The definition of insanity is doing the same thing over and over again and expecting different results.

    Matthew Yglesias » Israel’s Irrealism on Settlements


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  • 'Insanity- doing the same thing over and over and expecting different results.' -Albert Einstien

    February 18, 2008