toxin

noun2

1. •
   A toxic substance, specifically a poison produced by the biological processes of organisms.

   • The blue-ringed octopus Hapalochlaena lunulata has tetrodotoxin, the deadly toxin it also releases in a bite, in their ink but the concentrations and effect in inking are not known. — 2017
2. •
   (nonstandard) Synonym of toxicant: a toxic substance in a body requiring removal.