Real Dictionary

whir in American English
a sound like this, as that made by a bird's wings or a propeller
to fly, revolve, vibrate, or otherwise move quickly with a whizzing or buzzing sound
intransitive verb: to go, fly, revolve, or otherwise move quickly with a humming or buzzing sound
noun: an act or sound of whirring
transitive verb: to move or transport (a thing, person, etc.) with a whirring sound

whir in British English
noun: a prolonged soft swish or buzz, as of a motor working or wings flapping
verb: to make or cause to make a whir