Idiot
From my critical thinking course reading, I've learned an interesting fact: The word idiot is a Greek term used to denote someone who is unacquainted with ethics. Interesting how usage of that word has mutated over the centuries, to us now using it to denote someone we find stupid, moronic. And perhaps that is the point: at one point in time a person was stupid if they were incapable of, or unwilling to, learn and make use of the tools of reason. Interestingly, where I was born, the word ignorant was frequently used to denote someone without manners, someone rude.