mental deficiency


Definition of mental deficiency

: a deficiency in cognitive functioning specifically : intellectual disability

Examples of mental deficiency in a Sentence

Recent Examples on the Web There doesn’t seem to be any negative neurological signs yet for physical or mental deficiencies. Rania Aniftos, Billboard, "Third Day's Mac Powell Asks for Prayers After Wife Suffers Brain Aneurysm," 2 Dec. 2019 Look at the real-world results of Donald Trump's erratic behavior, whether through mental deficiency or moral deficiency or some combination thereof. NBC News, "Meet the Press - August 25, 2019," 25 Aug. 2019 Then English gave his closing arguments, saying that McCoy was guilty, but only of second-degree murder, because of mental deficiencies. Jon Schuppe, NBC News, "Supreme Court to hear case of lawyer who defied client in murder trial," 12 Jan. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'mental deficiency.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of mental deficiency

1820, in the meaning defined above

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Time Traveler for mental deficiency

Time Traveler

The first known use of mental deficiency was in 1820

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Statistics for mental deficiency

Last Updated

20 Dec 2019

Cite this Entry

“Mental deficiency.” The Dictionary, Merriam-Webster Inc., Accessed 28 January 2020.

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More Definitions for mental deficiency

mental deficiency


Medical Definition of mental deficiency

: a deficiency in cognitive functioning specifically : intellectual disability

mental deficiency


Legal Definition of mental deficiency

: failure in intellectual development that is marked by low intelligence or mental retardation and that may result in an inability to function competently in society

More from Merriam-Webster on mental deficiency Encyclopedia article about mental deficiency

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showing steady, earnest care and effort

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