Somebody who gets confused and angry because they are dumb. Typically someone who yells nonsensical repeat sentences while refusing to calm down and listen to simple logic.
Larry was Dumbfused and angry at Sally for stopping him from walking in the road.
Someone who says the weirdest shit and is oftened confused putting them in harmful situations such as stabbing themselves with forks or slashing their faces with trees.
Girl #1: That Justin kid has a severe case of dumbassednes !
Girl #2: Yeah but hes so cute!