出典:Wiktionary
From the cant word nigmenog, denoting a very silly fellow, according to A New Dictionary of the Terms Ancient and Modern of the Canting Crew (c.1698).[1] Compare ning-nong.
Reduplicative from nigger that became a part of the slang lexicon of people from Maine and other parts of the United States around the middle of the 20th century. It has also been applied to any persons of color, including East Asians, but this is largely exclusive to the UK.