means for real. It is another word for really or seriously. It is usually used in combination with "Oh" as in "Oh nettah?!", which basically means "Oh for real?!" or "really".
Matt: What are you doing Saturday night?
Joey: Nothing much...I'm probably going to the movies. Why?
Matt: Because I got an extra front row ticket to the Astros game with your name on it.
Joey: Oh nettah?!
Matt: Nettah!
Joey: Nothing much...I'm probably going to the movies. Why?
Matt: Because I got an extra front row ticket to the Astros game with your name on it.
Joey: Oh nettah?!
Matt: Nettah!
by TexasrebelJD August 25, 2006