nonpareil vs unmatched

nonpareil is a noun but unmatched is not a noun.

Word	Noun	Adjective	Verb	Adverb
nonpareil	Yes	Yes	No	No
unmatched	No	Yes	No	No

As adjectives, nonpareil and unmatched are synonyms defined as:

Other synonyms of nonpareil include matchless, one, one and only, peerless, unmatchable, unrivaled, unrivalled.

nonpareil (noun)	unmatched (noun)
colored beads of sugar used as a topping on e.g. candies and cookies
a flat disk of chocolate covered with beads of colored sugar
model of excellence or perfection of a kind; one having no equal

nonpareil (adjective)	unmatched (adjective)
eminent beyond or above comparison	eminent beyond or above comparison
	of the remaining member of a pair