'Pestilent' definitions:

Definition of 'pestilent'

(from WordNet)
adjective
Exceedingly harmful [syn: baneful, deadly, pernicious, pestilent]
adjective
Likely to spread and cause an epidemic disease; "a pestilential malignancy in the air"- Jonathan Swift; "plaguey fevers" [syn: pestilent, pestilential, pestiferous, plaguey]

Definition of 'Pestilent'

From: GCIDE
  • 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]