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

Discussing the song, he quickly notes that “nincompoop” is derived from the Latin phrase “non compos mentis” meaning “not of sound mind.”

From Los Angeles Times

The lyrics of Mr. Trump’s recent foreign policy speech may have been non compos mentis but the music featured an authentic lilt.

From The Wall Street Journal

The conceit was impractical, to say the least, and most descriptions of the process suggested the auteur might finally have taken a turn toward non compos mentis.

From The Wall Street Journal

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 Literature

Some people shammed away this confession, and said he was non compos mentis; and had a mind, it seems, to assume the glory of being hanged for the greatest villain.

From Project Gutenberg