The courtier's reply is a name given by biologist PZ Myers to a form of argument which claims that the arguments of another party in a debate is plainly ignorant on the subject at hand and therefore wrong -- without actually explaining why they are wrong. Users of the courtier's reply often attempt to emphasize the supposed ignorance of the other party both as a belittling emotional appeal (an attempt at silencing) and to play up their own authority on the subject (an argument from authority).
Myers originally suggested the term in a parody of the general sense of many of the rebuttals to the atheistic arguments of Richard Dawkins (as set forth in The God Delusion and elsewhere). In the parody, belief in God is analogized to belief in the emperor's clothing in the famous children's story "The Emperor's New Clothes". The speaker ridicules Dawkins's failure to appreciate all the fine details that others have observed, while failing utterly (aside from various logical fallacies such as argument from popular belief) to provide any evidence that they actually exist.