arriviste vs unpleasant person

arriviste and unpleasant person both are nouns.

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

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

arriviste: a person who has suddenly risen to a higher economic status but has not gained social acceptance of others in that class
unpleasant person: a person who is not pleasant or agreeable

Other hypernyms of arriviste include disagreeable person.

arriviste (noun)	unpleasant person (noun)
a person who has suddenly risen to a higher economic status but has not gained social acceptance of others in that class	a person who is not pleasant or agreeable