fathead

plural fatheads

1. derogatoryAn idiot; a fool.

   You fathead! You forgot to put the milk in the fridge and now it's spoiled!

   1 more example

   ‘We were getting a grand shot of a charging rhino when the cameraman got scared and bolted. The fathead!’

   1932, Delos W. Lovelace, King Kong, published 1965, page 24

2. A cyprinid fish of the Mississippi valley, Pimephales promelas, the black-headed minnow.
3. A labroid food fish of California; the California sheephead. Semicossyphus pulcher.
4. A blobfish, Psychrolutes microporos
5. Any of several species of fish of the genus Cubiceps