A derivative of filth. Meaning lower than specks of dust on your shoes.
Man, that is pure firth!
de Crismon 16 juin 2003
The process of being penetrated in the booty hole while giving birth.
Christopher is a firth baby.
de CupDude 17 février 2009
Puss-filled bubble, usually located around the anus.
"Yo, is that Firth in that Chevy?"
de Dr. Curtis 6 décembre 2003