insanity
n.the state of being seriously mentally ill or acting in a very foolish way. You use this word to describe behavior that makes no sense or seems dangerous.
n.a state of extreme mental illness or severe cognitive impairment; colloquially, behavior that is extremely foolish or irrational. Often used in legal contexts to describe a lack of responsibility for one's actions.
“It would be pure insanity to drive in this storm.”
“The defense lawyer argued that his client was suffering from temporary insanity at the time of the incident.”
“The philosopher argued that the modern obsession with constant productivity is a form of collective insanity that ignores the fundamental human need for rest and reflection.”
Uncountable in both its medical and colloquial senses; rarely takes a plural form except in highly specialized literary contexts.
“The three jurors said after 40 hours, a lone male juror wouldn't agree with the rest of the panel to find Clancy not guilty by reason of insanity.”
“Experts say mother who killed her three children could be found not guilty by way of insanity, but she wouldn't go free.”
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: * insane + -ity: īnsānus (“unhealthy; insane”) + -itās *: Latin īnsānus (“unsound in mind; mad, insane”), from in- + sānus (“sound, sane”). Modern forms of roots: in- + sane * in- + sanity: in- (“lacking; without”) + sānitās (“health; sanity”) *: Latin sānitās (“sound in mind; sane”), from sānus + -itās. Modern forms of roots: sane + -ity
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.