classified vs unclassified

classified is a noun but unclassified is not a noun.

Word	Noun	Adjective	Verb	Adverb
classified	Yes	Yes	No	No
unclassified	No	Yes	No	No

classified (noun)	unclassified (noun)
a short ad in a newspaper or magazine (usually in small print) and appearing along with other ads of the same type

classified (adjective)	unclassified (adjective)
arranged into classes	not arranged in any specific grouping
official classification of information or documents; withheld from general circulation	not subject to a security classification