Whistling

verb

1. To make a shrill, high-pitched sound by forcing air through the mouth. To produce a whistling sound, restrictions to the flow of air are created using the teeth, tongue and lips.

   "Never whistle at a funeral."

2. To make a similar sound by forcing air through a musical instrument or a pipe etc.

   "The stream train whistled as it passed by."

3. To move in such a way as to create a whistling sound.

   "A bullet whistled past."

4. To send, signal, or call by a whistle.