referring to someone who has the intellect of human feces

when you're hungover as shit after a spending a night drunk as a skunk

Someone or something that is ignorant or worthless to the point of having no value. Also one who displays the fact that they have no common sense or knowledge in a subject.

A complete idiot. Seeing as shit doesn't have a brain, the person being compared to it could be called a mindless moron.

really stupid

really stupid

very dumb