v. t. - To clap or strike, as a bird its wings, a fish its tail, etc.; to flap.
v. t. - To turn suddenly, as something broad and flat.
v. i. - To strike about with something broad abd flat, as a fish with its tail, or a bird with its wings; to rise and fall; as, the brim of a hat flops.
v. i. - To fall, sink, or throw one's self, heavily, clumsily, and unexpectedly on the ground.
n. - Act of flopping.