boo fanny Share definition Flag A big mama butt that takes up a massive amount of space; a butt that is kinda scary "Man, Teresa's boo fanny is all over the place, she need to stop dancing!" boo fanny by HsirT OecoM October 30, 2007 0 0 Get merch Get the boo fanny mug. Buy Now — $32.95 See more merch
