dense

Adjective

• 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
    

• having high relative density or specific gravity
  • dense as lead
    

• hard to pass through because of dense growth
  • dense vegetation
    
  • thick woods
    

• permitting little if any light to pass through because of denseness of matter
  • dense smoke
    
  • heavy fog
    
  • impenetrable gloom
    

Related words

• Synonyms: 
  dim , dull , dumb , obtuse , slow , thick , heavy , impenetrable