upper class vs elite

upper class and elite both are nouns.

Word	Noun	Adjective	Verb	Adverb
upper class	Yes	No	No	No
elite	Yes	Yes	No	No

As nouns, elite is a hyponym of upper class; that is, elite is a word with a more specific, narrower meaning than upper class:

upper class: the class occupying the highest position in the social hierarchy
elite: a group or class of persons enjoying superior intellectual or social or economic status

Other hyponyms of upper class include elite group, aristocracy, gentry, people in power, ruling class.

upper class (noun)	elite (noun)
the class occupying the highest position in the social hierarchy	a group or class of persons enjoying superior intellectual or social or economic status

upper class (adjective)	elite (adjective)
	selected as the best