<p><strong>adjective</strong></p><ul><li>having due authority</li><li>having the sanction or weight of authority; an authoritative opinion</li><li>substantiated or supported by documentary evidence and accepted by most authorities in a field; an authoritative edition of Shakespeare; an authoritative treatment of a subject</li><li>having an air of authority</li><li>accustomed to exercising authority</li><li>positive</li><li>peremptory</li><li>dictatorial; said with an authoritative air</li></ul>