deadly

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

of an instrument of certain death; "deadly poisons"; "lethal weapon"; "a lethal injection"

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

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

exceedingly harmful

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

as if dead

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