Definition of "classified"

classified¹

verb
1. simple past and past participle of classify
adjective
comparative more classified, superlative most classified
1. Sorted into classes or categories.
2. Formally assigned by a government to one of several levels of sensitivity, usually (in English) top secret, secret, confidential, and, in some countries, restricted; thereby making disclosure to unauthorized persons illegal.
  Quotations
  Charlie: Where did you see this?Maverick: That's classified. I could tell you, but then I'd have to kill you.Charlie: I have Top Secret clearance. The Pentagon sees to it that I know more than you.
  1986, Jim Cash, Jack Epps Jr., Top Gun (motion picture)
3. Not meant to be disclosed by a person or organization.

classified²

noun
plural classifieds
1. (informal) A classified advertisement in a newspaper or magazine.