<p><strong>Noun</strong></p><ul><li>an act or instance of knocking out.</li><li>the state or fact of being knocked out.</li><li>a knockout blow.</li><li>a person or thing overwhelmingly attractive, appealing, or successful.</li><li>a panel in a casing, can, or box, especially of metal or plastic, so designed that it can readily be removed, as by punching, hammering, or cutting, to provide an opening into the interior: a knockout in a junction box.</li><li>a device for knocking something loose, as finished work from a lathe chuck.</li></ul><p><strong>Adjective</strong></p><ul><li>that knocks out: the knockout punch.</li></ul>