copacetic

Origin: Stephen Goranson says "there is good reason to think that Irving Bacheller invented the word [with the spelling copasetic] for a fictional character with a private vocabulary in his best-selling and later-serialized 1919 book about Abraham Lincoln in Illinois, A Man for the Ages", and its currency increased by use in the 1920 song "At the New Jump Steady Ball" (see quotation below). Alternatively, it has been speculated that it may have originated among African Americans in the Southern US in the late 19th or early 20th century, perhaps specifically in the jargon of Bill "Bojangles" Robinso. Origin information sourced from Wiktionary contributors (CC BY-SA 4.0).