Synonyms for Big Mouth

Volubility
big mouth candor fluency frankness	gift of gab glibness gush loquacity	openness prolixity slush sociability	verbosity volubility

Braggart
big mouth blower blowhard brag	braggart bully gasbag hector	peacock ranter rodomontade swaggerer	swashbuckler windbag windjammer