What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
adjective
dated, offensive1Less advanced in mental, physical, or social development than is usual for one's age.
‘the child is badly retarded’‘they're treated as if they're mentally retarded’‘perhaps I'm emotionally retarded’- 1.1informal Very foolish or stupid.‘in retrospect, it was a totally retarded idea’
- 1.1informal Very foolish or stupid.
Usage
In the sense ‘less advanced in development than is usual for one's age’, retarded dates from the late 19th century. It has acquired offensive connotations in recent decades, and terms such as developmentally disabled or having intellectual disabilities are now preferred
