plague vs afflict

plague is a noun but afflict is not a noun.

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

As verbs, afflict is a hypernym of plague; that is, afflict is a word with a broader meaning than plague:

Other hypernyms of plague include smite.

plague (noun)	afflict (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

plague (verb)	afflict (verb)
annoy continually or chronically	cause physical pain or suffering in
cause to suffer a blight	cause great unhappiness for; distress