Retardfucker 

Someone who is fucking/ having sex with a retard. Not necessarily someone with mental retardation though just someone they've name-called a retard.

Guy: You're a retard!

Girl: If i'm a retard then what does that make you?

Guy: A retardfucker :D

Retardfucker by girlwhocriedhippo February 3, 2010

Retard Fucker 

A person who fucks retards.

Yo, dude! You see that kid over there?! Haha, he's such a retard fucker!

Retard Fucker by Mike Hansen June 20, 2004