(noun; adjective) An obese version of a muffin top; when the roll of fat or flab hanging over the top of the pants is just plain BIG. You know it when you see it. When it is just way too big to simply be referred to as a muffin top. A J-U-M-B-O muffin top.
Good lord; that's no muffin top - THAT'S a Bundt Cake!
That Bundt Cake will never fit into the center seat on that 727; it'll spill over into half of the seats on both sides.