blabbermouth

[ blab-er-mouth ]
/ ˈblæb ərˌmaʊθ /

noun, plural blab·ber·mouths [blab-er-mouthz, -mouths] /ˈblæb ərˌmaʊðz, -ˌmaʊθs/.

a person who talks too much, especially indiscreetly.

Origin of blabbermouth

An Americanism dating back to 1935–40; blabber + mouth
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for blabbermouth

British Dictionary definitions for blabbermouth

blabbermouth

/ (ˈblæbəˌmaʊθ) /

noun

informal a person who talks too much or indiscreetly
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012