'Toxicant' definitions:

Definition of 'toxicant'

From: WordNet
adjective
Having the qualities or effects of a poison [syn: poisonous, toxicant]
noun
Any substance that causes injury or illness or death of a living organism [syn: poison, toxicant, poisonous substance]

Definition of 'Toxicant'

From: GCIDE
  • Toxicant \Tox"i*cant\, n. A poisonous agent or drug, as opium; an intoxicant. [1913 Webster]