toxicity

from WordNet (r) 3.0 (2006)

toxicity
    n 1: the degree to which something is poisonous
    2: grave harmfulness or deadliness [syn: {perniciousness},
       {toxicity}]

from The Collaborative International Dictionary of English v.0.48

Toxicity \Tox*ic"i*ty\, n.
   The quality or state of being toxic or poisonous;
   poisonousness.
   [Webster 1913 Suppl.]

from Moby Thesaurus II by Grady Ward, 1.0

29 Moby Thesaurus words for "toxicity":
      balefulness, banefulness, communicability, contagiousness,
      deadliness, destructiveness, detrimentalness, harmfulness,
      hurtfulness, infectiousness, infectivity, injuriousness, lethality,
      malignance, malignancy, malignity, mischievousness, noisomeness,
      noxiousness, ominousness, perniciousness, poison, poisonousness,
      unhealthiness, venom, venomousness, viciousness, virulence,
      virulency