<p><strong>Verb (used with object)</strong></p><ul><li>to move from side to side, forward and backward, or up and down, especially rapidly and repeatedly: a dog wagging its tail.</li><li>to move (the tongue), as in idle or indiscreet chatter.</li><li>to shake (a finger) at someone, as in reproach.</li><li>to move or nod (the head).</li></ul><p><strong>Verb (used without object)</strong></p><ul><li>to be moved from side to side or one way and the other, especially rapidly and repeatedly, as the head or the tail.</li><li>to move constantly, especially in idle or indiscreet chatter: Her behavior caused local tongues to wag.</li><li>to get along; travel; proceed: Let the world wag how it will.</li><li>to totter or sway.</li><li>British Slang: to play truant; play hooky.</li></ul><p><strong>Noun</strong></p><ul><li>the act of wagging: a friendly wag of the tail.</li><li>a person given to droll, roguish, or mischievous humor; wit.</li></ul>