deadly in WordNet English dictionary

1. exceedingly harmful
   baneful  deadly  pernicious  pestilent 
   
2. extremely poisonous or injurious; producing venom
   "venomous snakes"; "a virulent insect bite"
   deadly  venomous  virulent 
   
3. involving loss of divine grace or spiritual death
   "the seven deadly sins"
   deadly  mortal 
   
4. (of a disease) having a rapid course and violent effect
   deadly 
   
5. causing or capable of causing death
   "a fatal accident"; "a deadly enemy"; "mortal combat"; "a mortal illness"
   deadly  deathly  mortal 
   
6. of an instrument of certain death
   "deadly poisons"; "lethal weapon"; "a lethal injection"
   deadly  lethal 
   

1. (used as intensives) extremely
   "she was madly in love"; "deadly dull"; "deadly earnest"; "deucedly clever"; "insanely jealous"
   madly  insanely  deadly  deucedly  devilishly  madly  insanely  deadly  deucedly  devilishly 
   
2. as if dead
   deadly  lifelessly  deadly  lifelessly