1.
of, pertaining to, affected with, or caused by a toxin or poison: a toxic condition.
2.
acting as or having the effect of a poison; poisonous: a toxic drug.
3.
pertaining to or noting debt that will probably not be repaid: toxic mortgages.
4.
pertaining to or noting a financial instrument or other asset that has no value or an unknown value because there is no market for it: toxic mortgage-backed securities.
http://dictionary.reference.com/browse/toxic?s=t
please stop with this fucking word