Per*ni"cious*ness

from The Collaborative International Dictionary of English v.0.48
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.
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         Pernicious to his health.                --Prescott.
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   Syn: Destructive; ruinous; deadly; noxious; injurious;
        baneful; deleterious; hurtful; mischievous.
        [1913 Webster] -- {Per*ni"cious*ly}, adv., --
        {Per*ni"cious*ness}, n.
        [1913 Webster]