flutter
/ˈflə-tər/
verb
to flap the wings rapidly
to move with quick wavering or flapping motions
to vibrate in irregular spasms
butterflies fluttering among the flowers
noun
an act of fluttering
a state of nervous confusion or excitement
flurry, commotion
noun
an alternating whipping motion of the legs used in various swimming styles (such as the crawl)