{adj.}, {slang} Talking noisily, boastfully, or foolishly. * /Fred was a loud-mouthed fellow, whose talk no one listened to./ * /If I were you, I would not listen to that loud-mouthed boy./
BIG-MOUTHED
Meaning of BIG-MOUTHED in English
Slang English vocab. Английский сленговый словарь. 2012