[hwis-uh
l, wis-] 
verb, -tled, -tling, noun | 1. | to make a clear musical sound, a series of such sounds, or a high-pitched, warbling sound by the forcible expulsion of the breath through a small opening formed by contracting the lips, or through the teeth, with the aid of the tongue. |
| 2. | to make such a sound or series of sounds otherwise, as by blowing on some device. |
| 3. | to emit similar sounds from the mouth, as birds do. |
| 4. | (of a device) to produce a similar sound when actuated by steam or the like: This teakettle whistles when it boils. |
| 5. | to move, go, pass, etc., with a whistling or whizzing sound, as a bullet or the wind. |
| 6. | to produce by whistling: to whistle a tune. |
| 7. | to call, direct, or signal by or as by whistling: He whistled his dog over. |
| 8. | to send with a whistling or whizzing sound. |
| 9. | an instrument for producing whistling sounds by means of the breath, steam, etc., as a small wooden or tin tube, a pipe, or a similar device with an air chamber containing a small ball that oscillates when air is forced through an opening, producing a high-pitched, warbling tone. |
| 10. | a sound produced by whistling: a prolonged whistle of astonishment. |
| 11. | a simple fipple flute. |
| 12. | whistle for, to demand or expect without success: After promising to pay, he told us we could whistle for our money. |
| 13. | blow the whistle, to expose the existence of mischief or wrongdoing: The agent was taking bribes until someone finally blew the whistle. |
| 14. | blow the whistle on,
|
| 15. | wet one's whistle, Informal. to take a drink. |
| 16. | whistle in the dark, to attempt to summon up one's courage or optimism in a difficult situation: He says his business will improve next year, but he's probably just whistling in the dark. |
blow the whistle on
Expose corruption or other wrongdoing, as in The President's speech blew the whistle on the opposition's leaking information. [Colloquial; 1930s]
Put a stop to, as in The registry decided to blow the whistle on new vanity plates. The term originally alluded to ending an activity (such as factory work) with the blast of a whistle. [Late 1800s]