bullethead

[boo l-it-hed]

noun

a head considered similar in shape to a bullet, as that of a person with a high, domelike forehead and cranium and short hair.
a person having such a head.
an obstinate or stupid person.

Origin of bullethead

First recorded in 1680–90; bullet + head

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

He was a short, thick-shouldered man with a bullethead that was covered with bristling, cropped hair.
A Yankee Flier with the R.A.F.
Rutherford G. Montgomery