copacetic

Stephen Goranson says "there is good reason to think that Irving Bacheller invented the word [with 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". 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" Robinson, who certainly helped popularize it in any case. Many hypotheses about its origin (etymon) exist, all lacking supporting evidence:
Possible origins
* That it derives from Cajun French coup esètique / coupersètique (“capable of being coped with successfully; able to cope with anything and everything”).
* That it derives from a word *copasetti used by Italian speakers in New York.
* That it derives from Chinook Jargon copasenee (“everything is satisfactory”) — if the Chinook Jargon term is not itself derived from English.
* The common suggestion that the term derives from Hebrew הכל בסדר (hakól b'séder, “everything is in order”) has been rejected, as has the fanciful suggestion that it derives from criminals' observation that they could go about their business because "the cop is on the settee".