fud

[fuhd]

noun Slang.

Origin of fud

First recorded in 1910–15; back formation from fuddy-duddy

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

Colonel Aoki stood in the midst of that as firm and unflinching as Ni- or Fud, staring at the enemy with steady gaze.
Human Bullets
Tadayoshi Sakurai

"backside, buttocks," 1785, a Scottish and Northern dialect word of unknown origin, perhaps from Scandinavian.