class act vs nonesuch

class act and nonesuch both are nouns.

Word	Noun	Adjective	Verb	Adverb
class act	Yes	No	No	No
nonesuch	Yes	No	No	No

As nouns, nonesuch is a hypernym of class act; that is, nonesuch is a word with a broader meaning than class act:

Other hypernyms of class act include apotheosis, ideal, nonpareil, nonsuch, paragon, saint.

class act (noun)	nonesuch (noun)
someone who shows impressive and stylish excellence	model of excellence or perfection of a kind; one having no equal