muffin top
n.— «For an unfriendly fashion that can render even slim young girls unsightly, with middles spilling over the top of tight jeans in what has become known as the “muffin top” effect, it has proved to be alarmingly enduring.» —“Gone belly up” by Alicia Pyke Courier-Mail (Queensland, Australia) July 29, 2004. (source: Double-Tongued Dictionary)