butterball

plural butterballs

1. A round lump of a coagulated fat used in cooking such as butter or margarine.
2. derogatoryhumorousslangAn overweight person.

   What if your baby is a butterball? Does Fat-Proofing mean you should put your infant on diet?.

   1988, Vicki Lansky, Fat-Proofing your Children – so that they Never Become Diet-Addicted Adults, page 62

3. A small North American duck, the bufflehead, Bucephala albeola.

   The skipper had his eye on a bunch of butterballs feeding not far from the boat. In fact there were ducks all around — though he did not tell me so.

   1917, Hunter-Trader-Trapper, volume 34, page 37