Sam Hill

noun, Slang.
1.
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
1830-40, Americanism; Sam (orig. salmon, variant of Sal(o)mon an oath) + hill, euphemism for hell
Word Origin and History for Sam Hill

euphemism for "Hell," 1839, American English, of unknown origin.

Slang definitions & phrases for Sam Hill

Sam Hill

noun phrase

Hell: Where in Sam Hill do you think you're going?

[1839+; an echoic euphemism]