mental impairment

noun

law (in England, according to the Mental Health Act 1983) a state of arrested or incomplete development of mind, which includes significant impairment of intelligence and social functioning and is associated with abnormally aggressive or seriously irresponsible conduct

Derived Formsmentally impaired, adjective

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