deadly

Adjective

• (of a disease) having a rapid course and violent effect

• exceedingly harmful

• involving loss of divine grace or spiritual death
  • the seven deadly sins
    

• extremely poisonous or injurious; producing venom
  • venomous snakes
    
  • a virulent insect bite
    

• of an instrument of certain death
  • deadly poisons
    
  • lethal weapon
    
  • a lethal injection
    

• causing or capable of causing death
  • a fatal accident
    
  • a deadly enemy
    
  • mortal combat
    
  • a mortal illness
    

Adverb

• (used as intensives) extremely
  • she was madly in love
    
  • deadly dull
    
  • deadly earnest
    
  • deucedly clever
    
  • insanely jealous
    

• as if dead

Related words

• Synonyms: 
  baneful , pernicious , pestilent , mortal(a) , venomous , virulent , lethal , deathly , mortal , madly , insanely , deucedly , devilishly , lifelessly