non compos mentis

American  

[nohn kohm-pohs men-tis, non kom-puhs men-tis] / ˈnoʊn ˈkoʊm poʊs ˈmɛn tɪs, ˈnɒn ˈkɒm pəs ˈmɛn tɪs /

adjective

Latin.

1. not of sound mind; mentally incapable of managing one's affairs (used especially in a legal context).

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non compos mentis British  

/ ˈnɒn ˈkɒmpəs ˈmɛntɪs /

adjective

1. mentally incapable of managing one's own affairs; of unsound mind

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non compos mentis Cultural  

1. A phrase used to describe someone who is out of his or her mind and therefore not legally responsible for his or her actions: “It was determined by the court that the killer was non compos mentis.” From Latin, meaning “not having control of the mind.”

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Etymology

Origin of non compos mentis

Latin: not in control of one's mind

Example Sentences

When you watch it, you can see quite clearly, with the benefit of hindsight, that he is non compos mentis.

From The Guardian • Sep. 8, 2010

In London, a coroner found that the late Sidney Corrall, acquisitive but non compos mentis, had swallowed and kept all to himself 201 pennies, florins, shillings, halfpennies, sixpences, half crowns, and threepenny bits.

From Time Magazine Archive

If anyone proposes another match race between these two super horses,” wrote a reporter after the race, “henceforth, he will be tried in the morning for treason, mutiny, mopery and non compos mentis.'''’

From "Seabiscuit: An American Legend" by Laura Hillenbrand

When in Omaha her mental peculiarities were recognized and she was studied by a competent alienist who, however, was not willing to render a verdict of non compos mentis to the police.

From Pathology of Lying, accusation, and swindling: a study in forensic psychology by Healy, William

Go, woman," said Mat; "did you ever know me to make a wrong calculation—I tell you I'm non compos mentis from head to heel.

From The Hedge School; The Midnight Mass; The Donagh Traits And Stories Of The Irish Peasantry, The Works of William Carleton, Volume Three by Carleton, William