One who or that which flaps. / (hunting) A young game bird just able to fly, particularly a wild duck. / A flipper; a limb of a turtle, which functions as a flipper or paddle when swimming.

(colloquial, historical) A young girl usually between the ages of 15 and 18, especially one not "out" socially.

plural of flapper

The behaviour of flappers (young women).

a fire beater

A European skate, Dipturus intermedius, a subspecies of the common skate.

plural of flapper skate

plural of fire flapper

A kind of valve used in toilets, water softeners, etc. to create a watertight seal in the tank that holds water until it needs to be flushed, at which point the valve is raised.

plural of flapper valve