whirr

Noun

• sound of something in rapid motion
  • whir of a bird's wings
    
  • the whir of the propellers
    

Verb

• make a vibrant sound, as of some birds

• make a soft swishing sound
  • the motor whirred
    
  • the car engine purred
    

Related words

• Synonyms: 
  whir , whirring , birr , churr , whizz , whiz , purr