Emily Dickinson Lexicon

CLACK, v.i. [Fr. claquer, to flap or snap; cliquet, a mill-clapper; cliqueter, to clack; W. cleca, clegyr; Ir. clagaim; D. klakken; Sax. cloccan, to cluck; L. glocio. Probably from the root of the L. loquor, Gr. λακω, ληκεω. See Cluck, and Class Lg, No. 27.]

1. To make a sudden sharp noise, as by striking or cracking; to clink; to click.
2. To utter words rapidly and continually, or with sharp, abrupt sounds; to let the tongue run.