Vagina Logic 

The ability of any woman to win an argument or prove a man wrong, based solely on the fact that she has a vagina.

Abigail proved Johnny wrong through vagina logic.

Vagina Logic by behle December 9, 2008

Vaginalogic 

The exact opposite of normal defined logic. Logic of the female species.

Illogical

nonsensical

Fred: "dude, I just don't understand why she acts like that...."
George: " I'll explain, your not using vaginalogic. It's completely different than the logic the rest of us use. Women just don't play by our rules man..."

Vaginalogic by KonohaSaint December 8, 2010