special vs uncommon

special is a noun but uncommon is not a noun.

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

special (noun)	uncommon (noun)
a special offering (usually temporary and at a reduced price) that is featured in advertising
a television production that features a particular person or work or topic
a dish or meal given prominence in e.g. a restaurant

special (adjective)	uncommon (adjective)
for a special service or occasion	not common or ordinarily encountered; unusually great in amount or remarkable in character or kind
first and most important	marked by an uncommon quality; especially superlative or extreme of its kind
adapted to or reserved for a particular purpose
having a specific function or scope
surpassing what is common or usual or expected
added to a regular schedule
unique or specific to a person or thing or category