toxic

/ˈtɑksɪk/

/ˈtɒksɪk/

Other forms: toxically

Danger! Hazardous! Do not eat! These are just some of the warnings you'll see on toxic substances — meaning stuff that's poisonous and even deadly.

Cobra bites, wild mystery mushrooms and strong chemicals are all toxic. So are certain people, if they have particularly mean personalities. Toxic is related to the word toxin, which is a kind of poison. It comes from the ancient Greek word toxikon, which means "poison for arrows." Some toxic arrows could come in handy for those toxic personalities...

Definitions of toxic

1. adjective

   of or relating to or caused by a toxin or poison
   “suffering from exposure to toxic substances”

   synonyms:

   harmful

   causing or capable of causing harm

   unhealthful

   detrimental to good health

   noxious

   injurious to physical or mental health

   cyanogenetic, cyanogenic

   capable of producing cyanide

   deadly, venomous, virulent

   extremely poisonous or injurious; producing venom

   hepatotoxic

   toxic to the liver

   nephrotoxic

   toxic to the kidney

   ototoxic

   toxic to the organs of hearing or balance or to the auditory nerve

   poisonous, toxicant

   having the qualities or effects of a poison

   antonyms:

   nontoxic

   not producing or resulting from poison

   harmless

   not causing or capable of causing harm

   antitoxic

   counteracting a toxin or poison

   non-poisonous, nonpoisonous

   not producing poison

   nonvenomous

   not producing venom