Farrah Abraham -- REJECTED By Playboy

INTERGALACTIC EXCLUSIVE: TMZ has learned, "Teen Mom" porn star Farrah Abraham will be living out every young girl's fantasy to model nude for Playboy magazine!!! Just kidding, Playboy rejected her sorry ass.

Sources tell us, the star of "Backdoor Teen Mom" reached out to the men's magazine following her sex tape release about appearing fully nude in an upcoming issue ... one of her lifelong dreams.

But the mag said no way, ho-se.

That didn't stop Farrah from trying one more time though -- we're told she reached out again last month ... and the magazine shot back with a SECOND NO, saying they just didn't have enough room for her.

Makes sense ... her new boobs are pretty damn big.