Found 2 items, similar to perniciousness.
English → English (WordNet) Definition: perniciousness perniciousness n : grave harmfulness or deadliness [syn: toxicity]
English → English (gcide) Definition: Perniciousness Pernicious \Per*ni"cious\, a. [L. perniciosus, from pernicies destruction, from pernecare to kill or slay outright; per + necare to kill, slay: cf. F. pernicieux. Cf. Nuisance, Necromancy.] Having the quality of injuring or killing; destructive; very mischievous; baleful; malicious; wicked. [1913 Webster] Let this pernicious hour Stand aye accursed in the calendar. --Shak. [1913 Webster] Pernicious to his health. --Prescott. [1913 Webster] Syn: Destructive; ruinous; deadly; noxious; injurious; baneful; deleterious; hurtful; mischievous. [1913 Webster] -- Per*ni"cious*ly, adv., -- Per*ni"cious*ness, n. [1913 Webster]