<p><strong>Verb (used without object)</strong></p><ul><li>to wave, flap, or toss about: Banners fluttered in the breeze.</li><li>to flap the wings rapidly; fly with flapping movements.</li><li>to move in quick, irregular motions; vibrate.</li><li>to beat rapidly, as the heart.</li><li>to be tremulous or agitated.</li><li>to go with irregular motions or aimless course: to flutter back and forth.</li></ul><p><strong>Verb (used with object)</strong></p><ul><li>to cause to flutter; vibrate; agitate.</li><li>to throw into nervous or tremulous excitement; cause mental agitation; confuse.</li></ul><p><strong>Noun</strong></p><ul><li>a fluttering movement: He made little nervous flutters with his hands.</li><li>a state of nervous excitement or mental agitation: a flutter of anticipation.</li><li>a small wager or speculative investment.</li></ul>