used to describe a situation in which everyone suddenly realizes that they were mistaken in believing that someone or something was very good, important, etc. Soon investors will realize that the emperor has no clothes, and there will be a big sell-off in stocks. From the story of The Emperor's New Clothes by Hans Christian Andersen, in which the emperor is tricked into thinking he is wearing beautiful new clothes and everyone pretends to admire them, until a little boy points out that he is naked.
Check pronunciation: emperor