late 14c., "the bones of the mouth," perhaps from Old French joue "cheek," from Gaulish *gauta "cheek," or perhaps a variant of Germanic words related to chew, q.v.; compare also jowl. Replaced Old English ceace, ceafl.

1610s, "to catch in the jaws, devour," from jaw, n.. In slang from 1748, "to gossip, to speak" 1810, "to scold." Related: Jawed; jawing. Hence 19c. U.S. slang jawsmith "talkative person" (1887).