Other forms: fluttering, flutters, fluttered
To flutter is to move the wings in quick light beats. A moth at a window, a bird settling on a wire.
It suits anything light caught by air: a flag fluttering, curtains fluttering, paper fluttering to the floor. The body borrows it for nerves, since a heart flutters and there are butterflies in the stomach to match. As a noun a flutter is both that quick movement and, in British informal use, a small bet — having a flutter on the Grand National. Medicine keeps a precise sense too, in atrial flutter.
Flutter is floating, over and over. Old English floterian is the frequentative of the verb to float, which makes a fluttering bird one that keeps floating.
Proto-Germanic
*flutrōną
Old English
floterian
Middle English
floteren
English, today
flutter
Built from
From Middle English floteren, from Old English floterian, flotorian (“to float about, flutter”), from Proto-Germanic flutrōną, frequentative of Proto-Germanic flutōną (“to float”), equivalent to float + -er. Cognate with West Frisian flodderje (“to flutter, beat”), Dutch flodderen (“to flutter, wave”), Low German fluttern, fluddern (“to flutter”), German flittern (“to sparkle, glitter”). More at float.
Etymology from Wiktionary, CC BY-SA