harass vs plague

harass is not a noun while plague is a noun.

Word	Noun	Adjective	Verb	Adverb
harass	No	No	Yes	No
plague	Yes	No	Yes	No

As verbs, harass and plague are synonyms defined as:

Other synonyms of harass include beset, chevvy, chevy, chivvy, chivy, harry, hassle, molest, provoke.

harass (noun)	plague (noun)
	an annoyance
	any large scale calamity (especially when thought to be sent by God)
	a swarm of insects that attack plants
	a serious (sometimes fatal) infection of rodents caused by Yersinia pestis and accidentally transmitted to humans by the bite of a flea that has bitten an infected animal
	any epidemic disease with a high death rate

harass (verb)	plague (verb)
exhaust by attacking repeatedly	annoy continually or chronically
annoy continually or chronically	cause to suffer a blight