A retard who's born with a few extra chromosomes and, as a result of this, feels obligated to vote down on every UD definition he comes across just because he feels like it.
Person A - Hey, why's that spaz voting down on that UD definition for crack? It's a perfect definition man!
Person B - Oh him? Yeah, he's just an Urban Dictionary Downer.
Person B - Oh him? Yeah, he's just an Urban Dictionary Downer.
by Urban Dictionary Upper February 18, 2010