/klak/ , v.i.
1. to make a quick, sharp sound, or a succession of such sounds, as by striking or cracking: The loom clacked busily under her expert hands.
2. to talk rapidly and continually or with sharpness and abruptness; chatter.
3. to cluck or cackle.
v.t.
4. to utter by clacking.
5. to cause to clack: He clacked the cup against the saucer.
n.
6. a clacking sound.
7. something that clacks, as a rattle.
8. rapid, continual talk; chatter.
[ 1200-50; ME clacken; imit. ]