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).
jaw (jô)
n.
Either of two bony structures that form the framework of the mouth and hold the teeth.
The mandible or maxilla or the part of the face covering these bones.
: ain't had a good jaw together (1842+)
verbbat one's gums, crack one's jaw, flapjaw, glass jaw, ratchet-mouth