classified vs top-secret

classified is a noun but top-secret is not a noun.

Word	Noun	Adjective	Verb	Adverb
classified	Yes	Yes	No	No
top-secret	No	Yes	No	No

classified (noun)	top-secret (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)	top-secret (adjective)
arranged into classes	the highest official level of classification of documents
official classification of information or documents; withheld from general circulation