class act vs nonsuch

class act and nonsuch both are nouns.

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

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

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

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