common vs uncommon

common is a noun but uncommon is not a noun.

Word	Noun	Adjective	Verb	Adverb
common	Yes	Yes	No	No
uncommon	No	Yes	No	No

common (noun)	uncommon (noun)
a piece of open land for recreational use in an urban area

common (adjective)	uncommon (adjective)
having no special distinction or quality; widely known or commonly encountered; average or ordinary or usual	not common or ordinarily encountered; unusually great in amount or remarkable in character or kind
belonging to or participated in by a community as a whole; public	marked by an uncommon quality; especially superlative or extreme of its kind
commonly encountered
of low or inferior quality or value
being or characteristic of or appropriate to everyday language
of or associated with the great masses of people
to be expected; standard
common to or shared by two or more parties
lacking refinement or cultivation or taste