<p><strong>Verb (used without object)</strong></p><ul><li>to smile broadly, especially as an indication of pleasure, amusement, or the like</li><li>to draw back the lips so as to show the teeth, as a snarling dog or a person in pain</li><li>to show or be exposed through an opening, crevice, etc.</li></ul><p><strong>Verb (used with object)</strong></p><ul><li>to express or produce by grinning: The little boy grinned his approval of the gift</li></ul><p><strong>Noun</strong></p><ul><li>a broad smile</li><li>the act of producing a broad smile</li><li>the act of withdrawing the lips and showing the teeth, as in anger or pain</li></ul>