dumb

Adjective

• unable to speak because of hereditary deafness

• lacking the power of human speech
  • dumb animals
    

• temporarily incapable of speaking
  • struck dumb
    
  • speechless with shock
    

• slow to learn or understand; lacking intellectual acuity
  • so dense he never understands anything I say to him
    
  • never met anyone quite so dim
    
  • although dull at classical learning, at mathematics he was uncommonly quick- Thackeray
    
  • dumb officials make some really dumb decisions
    
  • he was either normally stupid or being deliberately obtuse
    
  • worked with the slow students
    

Related words

• Synonyms: 
  mute , silent , speechless , dense , dim , dull , obtuse , slow