Definitions

1. adjective

having the most or highest degree of flapping motion, or being the most likely to flap.

“The flappiest bird in the forest was known for its impressive display of flying skills.”

2. superlative form of adjective

being the most flappy of all, or having the greatest degree of flapping motion.

“This is the flappiest kite I’ve ever seen, it can barely stay in the air.”