epidemic vs pestilential

epidemic is a noun but pestilential is not a noun.

Word	Noun	Adjective	Verb	Adverb
epidemic	Yes	Yes	No	No
pestilential	No	Yes	No	No

epidemic (noun)	pestilential (noun)
a widespread outbreak of an infectious disease; many people are infected at the same time

epidemic (adjective)	pestilential (adjective)
(especially of medicine) of disease or anything resembling a disease; attacking or affecting many individuals in a community or a population simultaneously	likely to spread and cause an epidemic disease