pestilent

from WordNet (r) 3.0 (2006)

pestilent
    adj 1: exceedingly harmful [syn: {baneful}, {deadly},
           {pernicious}, {pestilent}]
    2: likely to spread and cause an epidemic disease; "a
       pestilential malignancy in the air"- Jonathan Swift; "plaguey
       fevers" [syn: {pestilent}, {pestilential}, {pestiferous},
       {plaguey}]

from The Collaborative International Dictionary of English v.0.48

Pestilent \Pes"ti*lent\, a. [L. pestilens, -entis, fr. pestis
   pest: cf. F. pestilent.]
   Pestilential; noxious; pernicious; mischievous. "Corrupt and
   pestilent." --Milton. "What a pestilent knave is this same!"
   --Shak.
   [1913 Webster]

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