ain't done it Share definition Flag "Ain't done it (or dunnit)" is a Deep Southernism for "I emphatically repudiate your last allegation." . "Who took the last beer in the fridge? Jimmy, was it you?""Ain't done it!" ain't done it by al-in-chgo March 6, 2010 0 0 Get merch Get the ain't done it mug. Buy Now — $32.95 See more merch