What does "clack" mean?

Additional senses

1. 2.To cause to make a sudden, sharp noise, or succession of noises; to click.
2. 3.To utter rapidly and inconsiderately. Feltham. To clack wool, to cut off the sheep's mark, in order to make the wool weigh less and thus yield less duty. [Eng.]
3. 4.A sharp, abrupt noise, or succession of noises, made by striking an object.
4. 5.Anything that causes a clacking noise, as the clapper of a mill, or a clack valve.
5. 6.Continual or importunate talk; prattle; prating. Whose chief intent is to vaunt his spiritual clack. South. 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. 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.