intransitive. To make a sibilant sound of some kind; to whistle, hiss, whizz, or wheeze; transitive to whistle to.

transitive. To produce or utter by whistling (in sense 1 2, or 4), as a tune or melody; to express by whistling.

To whistle.

intransitive. To make a light whistling sound; transitive to utter with such a sound.

intransitive. To utter a somewhat protracted shrill cry, like the curlew or plover; also, to whistle feebly (intransitive and transitive).