dumbhead

[duhm-hed]

noun Slang.

Origin of dumbhead

First recorded in 1815–25; dumb + head

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

"You will be sorry for this, dumbhead," growled the prince, scowling fiercely.
The Valley of Vision
Henry Van Dyke
You're a man of remarkable resource, and I must be a dumbhead.
Get-Rich-Quick Wallingford
George Randolph Chester