v. i. [ imp. & p. p. Clacked p. pr. & vb. n. Clacking. ] [ Prob. of imitative origin; cf. F.claquer to clap, crack, D. klakken, MHG. klac crack, Ir. clagaim I make a noise, ring. Cf. Clack, n., Clatter, Click. ] 1. To make a sudden, sharp noise, or a succesion of such noises, as by striking an object, or by collision of parts; to rattle; to click. [ 1913 Webster ]

We heard Mr.Hodson's whip clacking on the ahoulders of the poor little wretches. Thackeray. [ 1913 Webster ]

2. To utter words rapidly and continually, or with abruptness; to let the tongue run. [ 1913 Webster ]

v. t. 1. To cause to make a sudden, sharp noise, or succession of noises; to click. [ 1913 Webster ]

2. To utter rapidly and inconsiderately. Feltham. [ 1913 Webster ]

To clack wool, to cut off the sheep's mark, in order to make the wool weigh less and thus yield less duty. [ Eng. ] [ 1913 Webster ]

n. [ Cf. F. claque a slap or smack, MHG. klac crack, W. clec crack, gossip. See Clack, v. t. ] 1. A sharp, abrupt noise, or succession of noises, made by striking an object. [ 1913 Webster ]

2. Anything that causes a clacking noise, as the clapper of a mill, or a clack valve. [ 1913 Webster ]

3. Continual or importunate talk; prattle; prating. [ 1913 Webster ]

Whose chief intent is to vaunt his spiritual clack. South. [ 1913 Webster ]

Clack box (Mach.), the box or chamber in which a clack valve works. --
Clack dish, a dish with a movable lid, formerly carried by beggars, who clacked the lid to attract notice. Shak. [ 1913 Webster ]

Clack door (Mining), removable cover of the opening through which access is had to a pump valve. --
Clack valve (Mach.), a valve; esp. one hinged at one edge, which, when raised from its seat, falls with a clacking sound. [ 1913 Webster ]

n. 1. One who clacks; that which clacks; especially, the clapper of a mill. [ 1913 Webster ]

2. A claqueur. See Claqueur. [ 1913 Webster ]

n. a fast and rhythmic clicking sound, as of “click-clack”; as, the clickety-clack of the typewriters.
Syn. -- clickety-clack. [ WordNet 1.5 ]