clack

Concise Oxford English Dictionary © 2008 Oxford University Press:
clack/klak/

▶verb

• 1 make or cause to make a sharp sound as of a hard object striking another.

• 2 archaic chatter loudly.

▶noun

• 1 a clacking sound.

• 2 archaic loud chatter.

– derivatives
clacker noun.

– origin ME: imitative.