WordNet sense 1 (a short ad in a newspaper or magazine (usually in small print) and appearing along with other ads of the same type):

classified ad, classified advertisement

WordNet sense 2 (the next to highest level of official classification for documents):

secret

WordNet sense 3 (the lowest level of official classification for documents):

restricted

WordNet sense 4 (the level of official classification for documents next above restricted and below secret; available only to persons authorized to see documents so classified):

confidential

WordNet sense 5 (arranged into categories):

categorized