Green’s Dictionary of Slang

1. an important person.

1903		‘Hugh McHugh’ Out for the Coin 30: Yo’ all was big Casino on the Eastern tracks, suh!
1904		R.F. Outcault ‘Buster Brown’ [comic strip] Speaking of the king, I passed the Queen and big casino in Hyde Park.
1911		Wibaux Pioneer (MT) 24 Feb. 4/2: Uncle Owen considered me big casino on the Eastern tracks.
1958		McCulloch Woods Words 11: Big casino – The head man, foreman.

2. a large person; thus little casino, a small person.

1908

B. Fisher A. Mutt in Blackbeard Compilation (1977) 128: A human hummingbird invariably grabs a female Taft and looks like big and little casino.

3. the best, the ultimate, the most important.

1922		P.A. Rollins Cowboy 80: Whatever idea or physical asset was expected when ultimately put in use to bring success was one’s ‘big casino.’ In the class of big casino were included not only schemes for outwitting rivals, but also powerful weapons presumably intimidating to enemies, attractive presents supposedly irresistible by females, speedy horses assumed to be invincible in racing.
1967		M. Braly On the Yard (2002) 282: He’s holding aces. But we’re holding big casino, little casino, cards, and spades. He’ll find that out.
1977		N.C. Heard When Shadows Fall 198: ‘Believe it or not, I don’t know much more than you. But I’ll tell you this: it’s the director’s baby and it’s big casino’ .

4. anything terminal, fatal, esp. a disease, e.g. cancer; also syphilis; thus little casino, a minor disease.

c.1930		(ref. to mid-19C) N. Kimball Amer. Madam (1981) 36: The two women infected a lot of the farm boys and hired hands with Little Casino (clap) and Big Casino (syphilis).
1952		(con. 1939) G. Fowler Schnozzola 207: He feared he had cancer, a disease referred to by Broadwayites as ‘Big Casino’. [Ibid.] 248: Lou has got Big Casino, like he always feared.
1960		Ocean’s Eleven [film script] Look, doc, give it to me straight, is it the Big Casino?
1968		S. Longstreet Wilder Shore 216: Seldom, before the age of penicillin, was a sailor [...] left uninfected by Big Casino or Little Casino, the major and minor diseases of Venus.
1971		T. Thackrey Thief 398: It was the Big Casino [...] it was shot all through him.
1986		T. Philbin Under Cover 21: His fingers came across a hard lump [...] God, he had touched the Big Casino.
2003		Guardian G2 17 Mar. 5: You see polyps, piles [...] ulcers, colitis, and the dreaded big casino.
2004		‘The Sopranos’ at hbo.com 🌐 Junior was placed under house arrest on federal racketeering charges and diagnosed with his own case of the ‘big casino,’ cancer.