blab (bl?b)v. blabbed, blab·bing, blabs v.tr. To reveal (secret matters), especially through indiscreet or unreserved talk.v.intr.1. To reveal secret matters indiscreetly.2. To chatter thoughtlessly or indiscreetly.n.1. An incessant or indiscreet talker.2. Lengthy chatter.[Middle English blabben, to talk foolishly, back-formation from blaberen.]blab?by adj.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.blabby (?blæb?) adj, blabbier or blabbiestinformal overly talkativeCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014