(1):

(v. t.) To vibrate or move quickly; as, a bird flutters its wings.

(2):

(n.) The act of fluttering; quick and irregular motion; vibration; as, the flutter of a fan.

(3):

(n.) Hurry; tumult; agitation of the mind; confusion; disorder.

(4):

(v. t.) To drive in disorder; to throw into confusion.