Why use pharisaical when you could say hypocritical? In general, you would probably use the word in especially severe cases of hypocrisy, particularly when someone is not only a hypocrite, but acts superior and is being particularly annoying about it. The word pharisaical can be traced all the way back to the Pharisees, an ancient Jewish group who insisted on the strict following of certain laws, though some people considered the group to be self-righteous.