n. & v.
n. 1 a clear shrill sound made by forcing breath through a small hole between nearly closed lips. 2 a similar sound made by a bird, the wind, a missile, etc. 3 an instrument used to produce such a sound.
v. 1 intr. emit a whistle. 2 a intr. give a signal or express surprise or derision by whistling. b tr. (often foll. by up) summon or give a signal to (a dog etc.) by whistling. 3 tr. (also absol.) produce (a tune) by whistling. 4 intr. (foll. by for) vainly seek or desire. as clean (or clear or dry) as a whistle very clean or clear or dry. blow the whistle on colloq. bring (an activity) to an end; inform on (those responsible). whistle down the wind 1 let go, abandon. 2 turn (a hawk) loose. whistle in the dark pretend to be unafraid. whistle-stop 1 US a small unimportant town on a railway. 2 a politician's brief pause for an electioneering speech on tour. 3 (attrib.) with brief pauses (a whistle-stop tour). whistling kettle a kettle fitted with a whistle sounded by steam when the kettle is boiling.
[ OE (h)wistlian (v.), (h)wistle (n.) of imit. orig.: cf. ON hv¡sla whisper, MSw. hvisla whistle ]