Used to describe someone who cannot shut up, talks with verbal diahorrea or who swears a lot- almost used in that case interchangeably with 'foulmouth'.
by whitecracker556 March 09, 2009

by Gritto October 09, 2003

Glen is such a fatmouth, I can't believe he ate that whole party size bag of Doritos in one sitting.
Man, I'm so hungry I could fatmouth a Fuddruckers 1/2lb burger right now.
Man, I'm so hungry I could fatmouth a Fuddruckers 1/2lb burger right now.
by Goo L January 08, 2021
