Pestilence
Part of speech: noun
Definition: Any epidemic disease that is highly contagious, infectious, virulent and devastating.
Plague
Part of speech: verb
Definition: To harass, pester or annoy someone persistently or incessantly.To afflict with a disease or other calamity.
Part of speech: noun
Definition: (used absolutely, usually capitalized: The Pest) The pestilent disease "Plague", caused by the virulent bacterium Yersinia pestis and mostly known by its variant form bubonic plague.An epidemic or pandemic caused by any pestilence, but specifically by the above disease.A widespread affliction, calamity or destructive influx, especially when seen as divine retribution.A grave nuisance, whatever greatly irritates
Example sentence: When self-delusion and self-flattery enter the mind-set of a product team and the metrics they judge themselves by, like the first plague rat coming onto a ship, the end is practically preordained.