The medical phenomena of a person's breathe literally smelling like fecal matter; a derogatory term for someone whose mouth smells like intestinal waste, or rotting protein.
"Go brush your teeth you little turd-muncher!"
A person who constantly has shit coming out of their mouth.
I can't believe you said that, you're such a turd muncher.
Somebody who munches turds
Kelly: hey sue, what are you doing tonight?
Sue: Not much kelly, how bout you?
Kelly: Thought I might watch a movie and munch some turds. Wanna come over?
Sue: Sounds great kel, I love munching turds!