flapping

that flaps or flap

flapping sails

An instance where one, or something, flaps.

The farmyard was dark and he tiptoed across it so that the turkeys wouldn't set up their gobbling and flapping.

A phonological process found in many dialects of English, especially American English and Canadian English, by which intervocalic /t/ and /d/ surface as the alveolar flap [ɾ] before an unstressed syllable, so that words such as "metal" and

The situation where a resource, a network destination, etc., is advertised as being available and then unavailable (or available by different routes) in rapid succession.

The unlicensed racing of horses or greyhounds.

Greyhound racing had its origins in whippet racing, which was derived in turn from hare coursing. By the early twentieth century, however, a form of dog racing held in 'flapping tracks' was a common pastime in the wastelands near working-class areas of industrial cities.

Flapping is racing which is not licensed by the Jockey Club. […] Anyone found participating in, or even attending, flapping races is liable to be warned off.