clack

Etymology

From Middle English clacken, clakken, claken, from Old English *clacian (“to slap, clap, clack”), from Proto-Germanic *klakōną (“to clap, chirp”). Cognate with Scots clake, claik (“to utter cries", also "to bedaub, sully with a sticky substance”), Dutch klakken (“to clack, crack”), Low German klakken (“to slap on, daub”), Norwegian klakke (“to clack, strike, knock”), Icelandic klaka (“to twitter, chatter, wrangle, dispute”).

noun

1. An abrupt, sharp sound, especially one made by two hard objects colliding repetitively; a sound midway between a click and a clunk.
2. Anything that causes a clacking noise, such as the clapper of a mill, or a clack valve.
3. Chatter; prattle.
4. (colloquial) The tongue.

verb

1. (intransitive) To make a sudden, sharp noise, or succession of noises; to click.
   [He] walked quite jauntily across the courtyard to the distant door, his sandals clacking against the marble. 1966, James Workman, The Mad Emperor, Melbourne, Sydney: Scripts, page 52
2. (transitive) To cause to make a sudden, sharp noise, or succession of noises; to click.
3. To chatter or babble; to utter rapidly without consideration.
   There is a generation of men, whose unweighed custome makes them clack out any thing their heedleſs fancy ſprings
   The women bunched up in little droves and let their tongues clack, and the men herded together and passed a jug around and, to tell the truth, let their tongues clack too. 1953, Janice Holt Giles, The Kentuckians
4. (UK) To cut the sheep's mark off (wool), to make the wool weigh less and thus yield less duty.
5. Dated form of cluck.
   Only the chickens clacked at the Saturday quiet and fat mouse-minded cats licked whiskers on the empty steps. 1934, Gladys Bagg Taber, Late Climbs the Sun, page 30
   We drive on between meadows of mown grass, through a pergola of vines, and so to an orchard of peaches, apples, and pears and a hen colony housed in neat modern cottages, the chickens clacking and scratching away […] 1964, Frances Margaret Cheadle McGuire, Gardens of Italy, page 57