whir(noun, verb) noun1. sound of something in rapid motion- whir of a bird's wings- the whir of the propellersSimilar word(s): birr, whirr, whirringDefinition categories: event, sound verb1. make a soft swishing sound- the motor whirredSimilar word(s): birr, purr, whirr, whiz, whizzDefinition categories: perception, go, sound