gab

from The American Heritage® Dictionary of the English Language, 5th Edition.

• intransitive verb To talk idly or incessantly, as about trivial matters.
• noun Idle talk; chatter.

from The Century Dictionary.

• To project like a tusk.
• noun The mouth.
• noun Idle talk; chatter; loquacity.
• To jest; lie in jest; speak with exaggeration; lie.
• To talk idly; talk much; chatter; prate.
• To speak or tell falsely.
• noun A hook or crook; specifically, the hook on an eccentricrod which engages the wrist on the rock-shaft lever of a valve-motion.
• noun A jest; joke; mock; a piece of pleasantry.
• noun Same as gaub.

from the GNU version of the Collaborative International Dictionary of English.

• noun (Steam Engine) The hook on the end of an eccentric rod opposite the strap. See. Illust. of eccentric.
• noun colloq. The mouth; hence, idle prate; chatter; unmeaning talk; loquaciousness.
• noun [Colloq.] facility of expression.
• intransitive verb obsolete To deceive; to lie.
• intransitive verb To talk idly; to prate; to chatter.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun idle chatter
• noun mouth as gob
• verb intransitive, obsolete To jest; to tell lies in jest; exaggerate; lie.
• verb intransitive To talk or chatter a lot, usually on trivial subjects.
• verb transitive, obsolete To speak or tell falsely.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb talk profusely
• noun light informal conversation for social occasions