Green’s Dictionary of Slang

a general intensifier for a question.

1866		H.L. Williams N.-Y. After Dark 28: What in ---’s that?
1867		H.L. Williams Ticket-of-Leave Man 18: Now, what in h— and all is the girl gaping at?
1877		Chicago Sporting Gazette 4 Aug. n.p.: Whatinell has become of little drunken May Willard?
1878		F.H. Hart Sazerac Lying Club 176: What in blazes do you want to do with sugar?
1914		Day Book (Chicago) 26 May 21: McDougald has $5,000,000 cold cash [...] and he doesn’t know what in blazes to do with it.
1922		M.E. Smith Adventures of a Boomer Op. 32: What in H— is the matter with you?
1923		R. McAlmon Companion Volume 51: What in fucking hell do youse think this is, a sunday school picnic.
1927		B. Fisher ‘Mutt and Jeff’ [comic strip] How in h— does he do it?
1932		(con. 1910s) J.T. Farrell Young Lonigan in Studs Lonigan (1936) 2: Eli Whitney invented the cotton gin or whatever in hell. [Ibid.] 7: But why in hell shouldn’t they know?
1932		Z. Grey Robbers’ Roost 9: Wal now, whatinhell is this fussy old geezer about?
1937		(con. 1905–25) E.H. Sutherland Professional Thief (1956) 166: Considering that the guy is stealing over a period of years, where in the Hell is he going to eat?
1942		S. O’Casey Red Roses for Me Act I: Why in hell didn’t you tell me all this before?
1948		(con. 1944) N. Mailer Naked and Dead 393: Then whyinhell can’t you put it down like that?
1951		J.D. Salinger Catcher in the Rye (1958) 152: When in hell are you going to grow up?
1953		J. Thompson Alcoholics (1993) 11: Doctor Murphy had stalked in and asked what in hell he had thought he was doing.
1963		B. Hecht Gaily, Gaily 22: Where in hell did you dig up Miss Van Arsdale?
1964		H. Selby Jr Last Exit to Brooklyn 257: How inthehell did she expect him ta know where she kept everything.
1969		‘Iceberg Slim’ Pimp 50: Why in the Hell don’t you stop reading it? [i.e. the Bible].
1970		D. Ponicsan Last Detail 176: What in the huckleberry hell is all of this about?
1972		(con. 1916) G. Swarthout Tin Lizzie Troop (1978) 42: How in holy hell would you know!
1978		P. Theroux Picture Palace 180: What in hell’s the Pig Dinner?