名詞 clack:

1. a sharp abrupt noise as if two objects hit together; may be repeated
   同義詞：clap
2. a simple valve with a hinge on one side; allows fluid to flow in only one direction
   同義詞：clack valve, clapper valve

動詞 clack:

1. make a rattling sound
   同義詞：clatter, brattle
2. make a clucking sounds, characteristic of hens
   同義詞：cluck, click
3. speak (about unimportant matters) rapidly and incessantly
   同義詞：chatter, piffle, palaver, prate, tittle-tattle, twaddle, maunder, prattle, blab, gibber, tattle, blabber, gabble

1. He clack the nut open.
   他把堅果敲開。

clack

v.（動詞）
clacked,clack.ing,clacks
v.intr.（不及物動詞）
To make an abrupt, sharp sound, as in the collision of two hard surfaces.
噼啪作響：發(fā)出短促、尖銳的聲音，如兩個堅硬表面碰撞時的聲音
To chatter thoughtlessly or at length.
嘮叨，喋喋不休：缺少考慮地或冗長地說話
To cackle or cluck, as a hen.
咯咯地叫，象母雞一樣
v.tr.（及物動詞）
To cause to make an abrupt, sharp sound.
使發(fā)出短促、尖銳的聲音
n.（名詞）
A clacking sound:
噼啪的響聲：
例句：
the clack of an old-fashioned typewriter.
一臺老式打字機的噼啪響聲

Something that makes a clacking sound.
發(fā)出噼啪響聲的物件
Thoughtless, prolonged talk; chatter.
喋喋不休：愚蠢的、冗長的談話；嘮叨

來源：
Middle English clakken
中古英語 clakken
from Old Norse klaka
源自 古斯堪的納維亞語 klaka
[of imitative origin]
[擬聲詞]

【引伸】
clack.er
n.（名詞）