Green’s Dictionary of Slang

1. (US, also Mexi) a Mexican; a nickname for a Mexican.

1848		S.C. Reid Scouting Adventures of McCullochs Texas Rangers 204: Look here, boys, do you see those two Mexes on the corner of the house opposite me?
1899		Boy’s Own Paper 15 July 658: The Mexies are cooking a beautiful curry.
1906		McClure’s Mag. June 121/1: ‘Where’d you get the coat?’ I asked the Mex [DA].
1914		Day Book (Chicago) 18 Apr. 31/1: By jingo, those Mex have got to salute the flag by shooting off 21 guns.
1925		D. Hammett ‘Corkscrew’ Story Omnibus (1966) 212: A big, black-whiskered Mex that’s got a rancho down the cañon.
1935		R. Chandler ‘Spanish Blood’ in Spanish Blood (1946) 27: My blood is Spanish, pure Spanish. Not nigger-Mex and not Yaqui-Mex.
1948		(con. 1944) N. Mailer Naked and Dead 66: Fugged if I’ll take an order from a Mex.
1956		N. Algren Walk on the Wild Side 36: City unions teach you that Chinamens are your brothers! Ayrabs! Mexes!
1966		M. Rumaker Exit 3 and Other Stories 58: Them goddamn Mex’s is all chicken shit.
1977		J.G. Dunne True Confessions (1979) 9: Boyle Heights was tough mick then, just like it’s tough Mex now.
1986		R. Campbell In La-La Land We Trust (1999) 134: ‘The dark-skinned girl was the one came in here for coffee?’ ‘That’s right. She was a Mex.’.
2001		(con. 1964–8) J. Ellroy Cold Six Thousand 288: A Mex brought coffee. Said Mex kissed ass.

2. (US) the Mexican/Spanish language.

1858		T.G. Vielé Following The Drum 158: Very little conversation took place between them, and that little in a language called ‘Mex,’ a kind of Spanish patois differing widely from pure Castilian.
1933		N. Algren ‘So Help Me’ in Texas Stories (1995) 19: I yelled back, you yellow Mexican bastard you, oney I said it in Mex.
1949		N. Algren Man with the Golden Arm 159: Can you talk Mex?
1959		J. Thompson Getaway in Four Novels (1983) 9: El Rey — that means the King, y’know, in Mex.

3. (US) Mexico; thus Mex City, Mexico City.

1885		S.S. Hall Gold Buttons 2: I war tole yer follered some [...] clean inter Ole Mex’ [HDAS].
1909		C. Fowler letter 8 Apr. in Tomlinson Rocky Mountain Sailor (1998) 366: Don't be afraid to spread yourself, Mex. is still cheap [...] so order everything on the calendar that suits your fancy.
1950		Kerouac letter 27 Dec. in Charters I (1995) 244: 3 wonderful lazy years perhaps in provincial Mexico (cheaper than Mexcity).

4. (US) Mexican money.

1898		Amer. Soldier (Manila) 11 Dec. n.p.: We will send a set [...] to any address in America for 25 cents (mex).
1906		C. M’Govern ‘Soldier Sl.’ in Sarjint Larry an’ Frinds n.p.: mex [...] the name for the kind of bastard currency in use during the Days of the Empire, one dollar of American money being about equal to two dollars of the Mexican.
1913		McClure’s Mag. Mar. 119: Is that gold or Mex, dear?
1924		Our Navy 15 July 29: A boot who was worth about six cents Mex to the government.
1930		(con. 1900s–10s) Dos Passos 42nd Parallel in USA (1966) 269: Just in time he noticed that the Syrian was giving him hundred dollars mex.

5. (US drugs) Mexican drugs.

1959		W. Brown Teen-Age Mafia 107: This pot’s real beat stuff. You know where we can pick up some Mex?
1982		L. Gwin Going Overboard 245: A certain guy with bags of good Mex for forty dollars [HDAS].