one vs incomparable

one is a noun but incomparable is not a noun.

Word	Noun	Adjective	Verb	Adverb
one	Yes	Yes	No	No
incomparable	No	Yes	No	No

one (noun)	incomparable (noun)
a single person or thing
the smallest whole number or a numeral representing this number

one (adjective)	incomparable (adjective)
used of a single unit or thing; not two or more	such that comparison is impossible; unsuitable for comparison or lacking features that can be compared
being a single entity made by combining separate components
(informal) very; used informally as an intensifier
eminent beyond or above comparison
indefinite in time or position
of the same kind or quality
having the indivisible character of a unit