retarded

nouns

people collectively who are mentally retarded
"he started a school for the retarded"

adjectives

relatively slow in mental or emotional or physical development
"providing a secure and sometimes happy life for the retarded"
antonym
is similar to
retarded in intellectual development
is similar to
having a mental age of three to seven years
is similar to
having a mental age of between eight and twelve years
is similar to
afflicted with cretinism
is similar to
not as far along as normal in development
is similar to
lacking mental capacity and subtlety
see also
lacking intelligence
"a dull job with lazy and unintelligent co-workers"