One whose mouth is constantly farted into, and who therefore has farty breath. To make matters worse, people like this tend to insist on talking loudly and constantly.
After that fartmouth got done yelling about child support for two hours, the entire room smelled like a big giant fart.
by hjgdshafgyewh November 24, 2010
a dumb ass
you fucking fart mouth, stoke my cock, eat my balls.
by dfg January 03, 2004