Lacking a prominent belly.
1Let go that cordelle, you cussed, lazy, flat-bellied, Hockhocking idiot!
2Every man and dog of us was as lean and flat-bellied as a board, and as hard.
3And I was setting forth on a buried-treasure expedition on a snub-nosed, flat-bellied, fresh-water ferry-boat, bound for Jersey City!
4The flat-bellied Mars glider would have measured a whopping 125 feet long and 95 feet across its delta wings.