<p><strong>adjective</strong></p><ul><li>Not mentionable; inappropriate, unfit, or improper for mention, as in polite conversation; unspeakable.</li></ul><p><strong>noun</strong></p><ul><li>Something that is not to be mentioned: That subject was classed among the unmentionables.</li><li>Unmentionables, undergarments.</li><li>(Formerly) trousers or breeches.</li></ul>