A combination of the word nigger, and tomfoolery. It is used to describe an annoying act, which is also commonly associated with being black. If you are at a party, and someone eats all of the watermelon and/or chicken, and drinks all the Kool Aid or other fruit drinks, this person has just committed Nignoggery. Although this is the best use of the word, any annoying act can be called Nignoggery, but it not loses any connection to being black, and is just a ridiculous word used in place of "shinanigans" and "tomfoolery".
Derrick- " Yo, let me get that last glass of Kool Aid and that last piece of Fried Chicken?! "
Lexe- " Derrick, you need to cut out the Nignoggery. "