pestilence (n.)youdaoicibaDictYouDict
c. 1300, from Old French pestilence "plague, epidemic" (12c.) and directly from Latin pestilentia "a plague, an unwholesome atmosphere," noun of condition from pestilentem (nominative pestilens) "infected, unwholesome, noxious," from pestis "deadly disease, plague" (see pest).
pestilent (adj.)youdaoicibaDictYouDict
late 14c., from Latin pestilentem (nominative pestilens), from pestilis "of the nature of a plague," from pestis "deadly contagious disease" (see pest (n.)). Related: Pestilently.
pestilential (adj.)youdaoicibaDictYouDict
late 14c., from Medieval Latin pestilentialis, from Latin pestilentia "plague" (see pestilence). Related: Pestilentially.