Derivative from the word "rookie" meaning lacking general skills or experience, and "bear" the most terrifying and overpowering of all mammals. It is understood that individuals labeled as Rookbears are incredibly incapable at anything and pose a major danger to themselves and society. Think of a really really stupid bear.
an extremely tasty alcoholic conconction which involves pouring beer into a shallow glass then dropping a shot glass filled with rootbeer schnapps into the middle and guzzling it until it is gone.
Drunk: damn im drunk, i just took like 10 rootbeer barrels