To draw back the lips so as to show the teeth set nearly or quite together, as a snarling dog, or a person in pain or anger.Hence To smile with a similar distortion of the features; exhibit derision, stupid admiration, embarrassment, or the like, by drawing back the lips from the teeth with a smiling expression.To snarl with, as the teeth in grinning.To effect by grinning.n. The act of withdrawing the lips and showing the teeth; hence, a broad smile; especially, a forced, derisive, sardonic, or vacant smile.n. A snare or trap which snaps and closes when a certain part is touched.