▪ relating to or caused by poison: "toxic hazards"
2. very harmful or unpleasant in a pervasive or insidious way: "a toxic relationship"
3. denoting or relating to debt that has a high risk of default: "toxic debts"
▪ denoting securities that are based on toxic debt and for which there is not a healthy or functioning market:"the financial system has become clogged with toxic assets"
noun
1. poisonous substances.
Word Originmid 17th century: from medieval Latin toxicus ‘poisoned’, from Latin toxicum ‘poison’, from Greek toxikon (pharmakon) ‘(poison for) arrows’, from toxon ‘bow’.