To Whistle

1. (transitive, intransitive) 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.
2. (transitive, intransitive) To make a similar sound by forcing air through a musical instrument or a pipe etc.
3. (intransitive) To move in such a way as to create a whistling sound.
4. (transitive) To send, signal, or call by a whistle.