insanity Definition

  • 1the state of being seriously mentally ill; madness
  • 2extreme foolishness or irrationality

Using insanity: Examples

Take a moment to familiarize yourself with how "insanity" can be used in various situations through the following examples!

  • Example

    The defendant pleaded insanity as a defense.

  • Example

    The idea that the earth is flat is pure insanity.

  • Example

    The company's decision to invest all their money in a failing project was an act of insanity.

insanity Synonyms and Antonyms

Synonyms for insanity

Antonyms for insanity

Idioms Using insanity

  • to cause someone to become mentally ill or lose their mind


    The constant noise from the construction site next door was driving her to insanity.

  • to be an extremely foolish or irrational thing to do


    Investing all your life savings in a get-rich-quick scheme is the height of insanity.

  • to be crazy or mentally unstable


    I think he has bats in the belfry, he keeps talking to himself and laughing for no reason.

Phrases with insanity

  • a defense used in court to argue that a person was not responsible for their actions due to a temporary mental illness or defect


    The defendant claimed temporary insanity as a defense for his crime.

  • a legal term used to describe a mental state where a person is unable to distinguish right from wrong, and therefore cannot be held responsible for their criminal actions


    The court declared him not guilty by reason of criminal insanity.

  • pretending to be insane, usually to avoid punishment or to gain some other advantage


    He tried to avoid going to jail by feigning insanity, but the court saw through his act.

Origins of insanity

from Latin 'insanitas', meaning 'unhealthiness'


Summary: insanity in Brief

The term 'insanity' [ɪnˈsænəti] refers to a state of serious mental illness or madness, as well as extreme foolishness or irrationality. It can be used in legal contexts, such as 'The defendant pleaded insanity as a defense,' or in everyday language, such as 'The idea that the earth is flat is pure insanity.' The term also extends into phrases like 'drive someone to insanity,' and idioms like 'have bats in the belfry,' denoting craziness.

How do native speakers use this expression?