Whistle  —n. 1 clear shrill sound made by forcing breath through a small hole between nearly closed lips. 2 similar sound made by a bird, the wind, a missile, etc. 3 instrument used to produce such a sound. —v. (-ling) 1 emit a whistle. 2 a give a signal or express surprise or derision by whistling. B (often foll. By up) summon or give a signal to (a dog etc.) By whistling. 3 (also absol.) Produce (a tune) by whistling. 4 (foll. By for) vainly seek or desire. [old english]