nag vs unpleasant person

nag and unpleasant person both are nouns.

Word	Noun	Adjective	Verb	Adverb
nag	Yes	No	Yes	No
unpleasant person	Yes	No	No	No

As nouns, unpleasant person is a hypernym of nag; that is, unpleasant person is a word with a broader meaning than nag:

nag: someone (especially a woman) who annoys people by constantly finding fault
unpleasant person: a person who is not pleasant or agreeable

Other hypernyms of nag include disagreeable person.

nag (noun)	unpleasant person (noun)
an old or over-worked horse	a person who is not pleasant or agreeable
someone (especially a woman) who annoys people by constantly finding fault

nag (verb)	unpleasant person (verb)
remind or urge constantly
bother persistently with trivial complaints
worry persistently