retard

Noun

• a person of subnormal intelligence

Verb

• lose velocity; move more slowly
  • The car decelerated
    

• slow the growth or development of
  • The brain damage will retard the child's language development
    

• be delayed

• cause to move more slowly or operate at a slower rate
  • This drug will retard your heart rate
    

Related words

• Synonyms: 
  idiot , imbecile , cretin , moron , changeling , half-wit , decelerate , slow , slow down , slow up , check , delay
• Antonyms: 
  accelerate , speed up , speed , quicken