The Collaborative International Dictionary
flannelmouth
Redmouth \Red"mouth`\ (-mouth`), n. (Zo["o]l.) Any one of several species of marine food fishes of the genus Diabasis, or H[ae]mulon, of the Southern United States, having the inside of the mouth bright red. Called also flannelmouth, and grunt.
Wiktionary
flannelmouth
n. 1 (context informal dated English) One who speaks in an unclear, muffled, or sluggish manner. 2 (context informal dated English) One who speaks in a glib manner with the intent of deceive or manipulate others.
Usage examples of "flannelmouth".
He would stand on the fantail and harangue whoever would listen, flannelmouthed through aching gums.