clack /ˈklæk/
  (vt.)(vi.)□啪響
  Clack, n.
  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.
  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.
  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.
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  Clack v. i. [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.
  Clack v. t.
  1. To cause to make a sudden, sharp noise, or succession of noises; to click.
  2. To utter rapidly and inconsiderately.
  To clack wool, to cut off the sheep's mark, in order to make the wool weigh less and thus yield less duty. [Eng.]
  clack
       n 1: a sharp abrupt noise as if two objects hit together; may be
            repeated [syn: clap]
       2: a simple valve with a hinge on one side; allows fluid to
          flow in only one direction [syn: clack valve, clapper
          valve]
       v 1: make a rattling sound; "clattering dishes" [syn: clatter,
            brattle]
       2: make a clucking sounds, characteristic of hens [syn: cluck,
           click]
       3: speak (about unimportant matters) rapidly and incessantly
          [syn: chatter, piffle, palaver, prate, tittle-tattle,
           twaddle, maunder, prattle, blab, gibber, tattle,
           blabber, gabble]