Synonyms for Toxic:

adj.

harmful (adjective)
poisonous.
poisonous (adjective)
lethal, virulent, mephitic, septic, toxicant, poison, deadly, venomous, noxious.
unclean (adjective)
slovenly, infectious, filthy, sloppy, grubby, dirty, muddy, sordid, smutty, festering, unclean, grimy, unhygenic, putrid, unsanitary, dingy, dusty, disgusting, icky, offensive, impure, insalubrious, fetid, squalid, murky, shabby, grungy, defiled, scatological, obscene, septic, scruffy, mucky, foul, odious, crummy, untidy.
unhealthy (adjective)
contagious, noxious, pestilent, malignant, gangrenous, unhealthy, infected, diseased, insalubrious, contaminated, pathological, poisonous, unsanitary, unhygienic, septic, deadly, unwholesome.

n.

clean, clean up, carbon sink, biohazard, biological control, carbon-neutral, carbon trading, catalytic converter, biodegradable, the carbon cycle. foreclose, creditworthiness, financier, poison, extension, borrowing power, help, borrowing, debt collector, creditworthy, Mephitical, mephitic, compound interest, creditor. noxious (noun)
lethal.
toxic (noun)
deadly, hepatotoxic, toxicant, nephrotoxic, ototoxic, poisonous, venomous, cyanogenic, cyanogenetic, virulent.

Other synonyms:

Mephitical, mephitic. poison. virulent
virulent.
Other relevant words:
hepatotoxic, mephitic, nephrotoxic, lethal, cyanogenetic, cyanogenic, toxicant, Mephitical, venomous, ototoxic, poison, virulent.

Usage examples for toxic

  1. Of all the members of the group, it most rarely produces toxic symptoms. – Aids to Forensic Medicine and Toxicology by W. G. Aitchison Robertson
  2. Everybody who has heard the name probably knows that the manioc root is naturally poisonous, and that the toxic elements must be removed by pressure and desiccation before the flour can be made. – Two Years in the French West Indies by Lafcadio Hearn
  3. But 10 million children under 12 still live within four miles of a toxic waste dump. – Complete State of the Union Addresses from 1790 to the Present by Various