formerly used to refer to a person with learning difficulties
retardate in American English
(rɪˈtɑːrdeit)
noun
old-fashioned, offensive
a person who has learning difficulties
Word origin
[1955–60; prob. back formation from retardation]This word is first recorded in the period 1955–60. Other words that entered Englishat around the same time include: cassette, life-support, new wave, opioid, rite of passage