"Darkie" is a term that was historically used to refer to a person with dark skin color, particularly people of African descent. However, it is important to note that the term is considered derogatory and offensive today.
During an uncomfortable dinner scene, Belle's brother (an honorable Southern soldier who accepts the surrender) attempts to break the tension by telling a joke that starts «So there was this old darkie...» whereupon he's interrupted for some plot - related dialogue. (theendofcinema.net)
«The most unpleasant was when we had to humiliate Obama, comparing him with a monkey, using words like darkie, insulting the president of a big country,» he said. (engadget.com)