unexcelled vs best

unexcelled is not a noun while best is a noun.

Word	Noun	Adjective	Verb	Adverb
unexcelled	No	Yes	No	No
best	Yes	Yes	Yes	Yes

unexcelled (noun)	best (noun)
	the supreme effort one can make
	the person who is most outstanding or excellent; someone who tops all others

unexcelled (adjective)	best (adjective)
not capable of being improved on	(superlative of `good') having the most positive qualities
	(comparative and superlative of `well') wiser or more advantageous and hence advisable

unexcelled (verb)	best (verb)
	get the better of

unexcelled (adverb)	best (adverb)
	it would be sensible
	in a most excellent way or manner
	from a position of superiority or authority