Definition of flutters:
(v) :
(intransitive) To flap or wave quickly but irregularly.
(v) :
(intransitive) Of a winged animal: to flap the wings without flying; to fly with a light flapping of the wings.
(v) :
(intransitive) To be in a state of agitation or uncertainty.
(n) :
The act of fluttering; quick and irregular motion.
(n) :
A state of agitation.
(n) :
An abnormal rapid pulsation of the heart.