Usually Offensive. a developmental disorder characterized in varying degrees by a subnormal ability to learn, a substantially low IQ, and impaired social adjustment.
Origin of mental retardation
First recorded in 1900–15
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
psychiatry the condition of having a low intelligence quotient (below 70)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Subnormal intellectual development or functioning that is the result of congenital causes, brain injury, or disease and is characterized by any of various deficiencies, ranging from impaired learning ability to social and vocational inadequacy.mental deficiency
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
Below-average intellectual ability resulting from a genetic defect, brain injury, or disease, and usually present from birth or early infancy.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.