Definition of whirrs:
(v) :
(intransitive) To make a sibilant buzzing or droning sound.
(v) :
(transitive) To cause (something) to make such a sound.
(v) :
To move or vibrate (something) with a buzzing sound.
(n) :
A sibilant buzz or vibration; the sound of something in rapid motion.
(n) :
A bustle of noise and excitement.
(v) :
(intransitive) (of a panther) To make a vibrating sound in its throat when contented, much like the domestic cat’s purr.