upper crust vs elite

upper crust and elite both are nouns.

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

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

upper crust: 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 crust include elite group, aristocracy, gentry, people in power, ruling class.

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