a. 致命的, 传染性的, 有害的, 伤风败俗的, 引起瘟疫的

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.