When something such as a machine or an insect's wing whirrs, it makes a series of low sounds so quickly that they seem like one continuous sound. The camera whirred and clicked. the whirring sound of the film projector. Whirr is also a noun. He could hear the whirr of a vacuum cleaner. Variant of whir. to make a fairly quiet regular sound, like the sound of a bird or insect moving its wings very fast (Probably from a language)