A condescending term for Stupid Liberal. A libby-lib is someone who is a liberal, but has no idea why, and often behave quite childishly. Are known to interject their hatred of all-things-Bush into discussions as non-sequiturs, such as howling about the Iraq War during a convo about Hurricane Katrina, the American League Penant Race, or the merits of getting Chinese food for dinner.
Adam: "Dewd, Jim thinks that jacking taxes up to the moon will help the economy?"
Bob: "Don't bother with him bro'...he's a libby-lib; his brain is a logic-free environment."