Definition of retarded in English:

retarded

adjective

dated, offensive
  • 1Less 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. 1.1informal Very foolish or stupid:
      ‘in retrospect, it was a totally retarded idea’

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 It has acquired offensive connotations and has now been replaced by terms such as learning-disabled or having learning difficulties

Pronunciation

retarded

/rɪˈtɑːdɪd/