mental deficiency

noun

Definition of mental deficiency

: mental retardation

Recent Examples of mental deficiency from the Web

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.

First Known Use of mental deficiency

1856

in the meaning defined above

See Words from the same year

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Medical Dictionary

mental deficiency

noun

medical Definition of mental deficiency

: mental retardation

Law Dictionary

mental deficiency

noun

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