The term "Grand Poobah" is derived from the brilliant comic opera by Gilbert and Sullivan, The Mikado. In it, there's a character named "Poo-Bah." Poo-Bah has a long series of titles after his name, such as Commander-in-Chief, Lord Chief Justice, and Lord High Everything Else. According to Wikipedia, the term Grand Poobah is used today "as a mocking title for someone self-important or high-ranking and who either exhibits an inflated self-regard or who has limited authority while taking impressive titles." You may have met or heard of people who have given themselves several archaic and grandiose titles, thinking that a list of exalted honorifics gives them the importance and respect