Green’s Dictionary of Slang

1. Chicago (cf. Chi-town n.).

1899		J. Flynt Tramping with Tramps 356: We were on our way to ‘Chi,’ or Chicago, as polite people call it.
1907		J. London Road 126: ‘Chi’ (pronounced shy), by the way is the argot for ‘Chicago’.
1908		C. Sandburg letter 10 Nov. in Mitgang (1968) 79: I leave here for Chi on the 9:00.
1917		R. Lardner ‘Three Kings and a Pair’ in Gullible’s Travels 45: She’d be here in Chi; maybe they could find a flat right in this buildin’.
1929		W.R. Burnett Little Caesar (1932) 243: Now I’m gonna show you how they treat smart dagos in Chi.
1933		‘Goat’ Laven Rough Stuff 21: This garage was near Canal Street, the West Side of Chi., in among the tenement houses.
a.1940		‘Wise Egg’ in D. Wepman et al. Life (1976) 114: I’d carried a tray in a New York café, / Hopped bells in the hotels of Chi.
1944		R.L. Bellem ‘Killer’s Cure’ Hollywood Detective Mar. 🌐 You used to be a gun moll in Chi, which would ruin you in the movies.
1951		Kerouac letter 22 May in Charters I (1995) 315: That summer in queer Plymouth and 110-mi-an-hour Caddy and Chi and Detroit.
1962		B. Behan Brendan Behan’s Island (1984) 42: Boston, New York, Philly, Chi., L.A., etc.
1975		L. Rosten Dear ‘Herm’ 2: And I don’t mean the Loop in downtown Chi.
1992		B. Gifford Night People 95: I put Kid Magnolia against Basilio in Chi.

2. attrib. use of sense 1, as a nickname.

1902		J. London ‘Rods and Gunnels’ in Bookman XV (Aug.) 541–44: Chi Slim, as his ‘monica’ denotes, hailed from Chicago.
1904		St Paul Globe (MN) 7 Aug. 27/2: ‘Chi Pat’, or Patrick, late of Chicago [...] became cheery.

3. attrib. use of sense 1, pertaining to Chicago.

1919		in Columbia Press Yank Talk 9: Let the ‘Chi’ birds speak up.
1942		W. Winchell 19 May [synd. col.] One reason the Chi troupe of ‘Angel Street’ folded so quickly is [etc].
1953		‘Curt Cannon’ ‘The Death of Me’ in I Like ’Em Tough (1958) 101: He’s working for a Chi syndicate.
2001		(con. 1964–8) J. Ellroy Cold Six Thousand 82: Pete’s mobbed up. Chi-Mob connections implied.
2012		T. Piccirilli Last Kind Words 229: The Chi syndicate was here pulling the Thompson crew apart and stealing their business.