hell (used especially in WH-questions as a mild oath expressing exasperation and usually preceded by in or the): Who in Sam Hill are you?
Origin of Sam Hill
1830–40, Americanism; Sam (orig. salmon, variant of Sal(o)mon an oath) + hill, euphemism for hell
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for sam hill
Historical Examples of sam hill
It hurts me like Sam-Hill, sometimes, to have to hurt my little man-child.The Prairie Mother
euphemism for "Hell," 1839, American English, of unknown origin.
Online Etymology Dictionary, © 2010 Douglas Harper