Flutter means to move with quick, light, flapping motions. A butterfly flutters from flower to flower, its wings beating rapidly but gently. Flags flutter in the breeze, waving back and forth with a soft rippling motion. When a bird takes off from a branch, you might see its wings flutter for a moment before it glides away.

The word captures something delicate and trembling. Hearts flutter when people feel nervous excitement, like before stepping on stage for a school play. Eyelids flutter when someone is falling asleep or just waking up. Pages flutter when you flip through a book quickly.

As a noun, a flutter can also mean a brief state of excitement or agitation. If news of a surprise field trip causes a flutter of whispers and excitement in the classroom, everyone is buzzing with energy. A flutter of activity means short bursts of quick movement.

The word suggests lightness and quickness rather than heavy, sustained motion. A helicopter's rotors don't flutter; they spin powerfully. But a leaf falling from a tree might flutter down, twisting and turning gently as it drifts to the ground.