PESTILENTIAL
pestilent, pestilential, pestiferous, plaguey
(adjective) likely to spread and cause an epidemic disease; “a pestilential malignancy in the air”- Jonathan Swift; “plaguey fevers”
Source: WordNet® 3.1
Adjective
pestilential (comparative more pestilential, superlative most pestilential)
Of or relating to pestilence or plague.
(of people, animals, places or substances) Producing, spreading, promoting or infected with pestilence; causing infection.
Synonym: pestiferous
(of illnesses) Spreading in the manner of pestilence.
(of symptoms) Caused by pestilence.
(of a period of time) During which pestilence spreads.
(figurative) Having a harmful moral effect (especially one that is believed to spread in the manner of pestilence).
Synonym: pernicious
(figurative) Causing irritation or annoyance.
Synonyms: annoying, irritating, pestiferous, pestilent, troublesome, vexatious
Source: Wiktionary
Pes`ti*len"tial, a. Etym: [Cf. F. pestilentiel.]
1. Having the nature or qualities of a pestilence. "Sends the
pestilential vapors." Longfellow.
2. Hence: Mischievous; noxious; pernicious; morally destructive.
So pestilential, so infectious a thing is sin. Jer. Taylor.
Source: Webster’s Unabridged Dictionary 1913 Edition