American Dictionary of the English Language

BLAB, verb transitive

1. To utter or tell in a thoughtless manner; to publish secrets or trifles without discretion. It implies, says Johnson, rather thoughtlessness than treachery, but may be used in either sense.

2. To tell, or utter; in a good sense.

BLAB, verb intransitive To tattle; to tell tales.

BLAB, noun A babbler; a telltale; one who betrays secrets, or tell things which ought to be kept secret.