- flapper⇄flapper, noun, verb.
- flapper⇄noun 1. something that flaps. A broad fin is sometimes called a flapper.
2. a broad, flat, hanging piece; flap.
3. a young bird just able to fly.
4. (Informal.)
a. a young girl.
b. a rather forward and unconventional gi - flapper⇄v.i. to move with a loose, flapping motion.