Humbug refers to deceptive or nonsensical talk or behavior. It is often used to describe statements or actions that are insincere, misleading, or lacking in substance. The term can also imply a sense of annoyance or frustration with something that is perceived as trivial or unworthy of serious consideration. The word gained popularity in the 19th century, particularly through its use in literature, such as in Charles Dickens's "A Christmas Carol," where the character Ebenezer Scrooge famously exclaims, "Bah! Humbug!" This expression captures his disdain for the festive spirit and the perceived foolishness of holiday cheer.