Copacetic \koh-puh-SET-ik\ , adjective, verb;
1. Very satisfactory; fine
This American slang word is first attested in 1919 and is of unknown origin. Most of the Oxford English Dictionary citations connect the word with African American or prison culture, so it's not very surprising that the origin isn't documented.
Today's word and the first definition were both taken from Dictionary.com's 'Word of the Day' for Friday, September 23
Etymologies come from the Oxford English Dictionary and/or Etymonline.com