unclassified vs classified

unclassified is not a noun while classified is a noun.

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

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

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