What is the meaning of whirring?

noun

• Sound of something in rapid motion.
  • usage: "whir of a bird's wings"; "the whir of the propellers"
  • synonyms: whir, whirr, birr

verb

• Make a soft swishing sound.
  • usage: "the motor whirred"; "the car engine purred"
  • synonyms: whizz, whiz, whirr, whir, birr, purr
• Make a soft swishing sound.
  • usage: "the motor whirred"; "the car engine purred"
  • synonyms: whizz, whiz, whirr, whir, birr, purr
• Make a vibrant sound, as of some birds.
  • synonyms: churr, whirr

adjective

• Like the sound of rapidly vibrating wings. .