Clack — Defs

01 v. i. 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.

imp. & p. p. Clacked; p. pr. & vb. n. Clacking

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.
“We heard Mr.Hodson's whip clacking on the ahoulders of the poor little wretches.” — Thackeray.
2.
To utter words rapidly and continually, or with abruptness; to let the tongue run.

02 v. t. To cause to make a sudden, sharp noise, or succession of noises; to click.

Phrases & compounds

To clack wool — to cut off the sheep's mark, in order to make the wool weigh less and thus yield less duty

03 n. A sharp, abrupt noise, or succession of noises, made by striking an object.

1.
A sharp, abrupt noise, or succession of noises, made by striking an object.
2.
Anything that causes a clacking noise, as the clapper of a mill, or a clack valve.
3.
Continual or importunate talk; prattle; prating.
“Whose chief intent is to vaunt his spiritual clack.” — South.

Phrases & compounds

Clack box — 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.

Clack door — removable cover of the opening through which access is had to a pump valve.

Clack valve — a valve; esp. one hinged at one edge, which, when raised from its seat, falls with a clacking sound.