A term used to replace any noun. Literally...
The most common words it replaces are terms of endearment towards friends or acquaintances, usually guys.
A variation of the term is man-deggen whose use just depends on the context.
"Hey dude, what sup?"
Can be changed to: "Hey deggen, what sup?"
"Yo bromosexual that's a sick shirt you got there"
Can be changed to: " Yo man-deggen that's a sick az frigging shirt!"