(third-person singular simple present clacks, present participle clacking, simple past and past participle clacked)
- (intransitive) To make a sudden, sharp noise, or succession of noises; to click.
- To cause to make a sudden, sharp noise, or succession of noises; to click.
- To chatter or babble; to utter rapidly without consideration.
- (UK) To cut the sheep's mark off (wool), to make the wool weigh less and thus yield less duty.
From Middle English clacken, clakken, claken, from Old English *clacian ("to slap, clap, clack"; suggested by clacu (“din; harm, injury”)), from Proto-Germanic *klakōną (“to clap, chirp”), from Proto-Indo-European *glag- (“to make a noise, clap, twitter”), from Proto-Indo-European *gal- (“to roop, scream, shout”). 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”).