Green’s Dictionary of Slang

1. (also Maclander) a Celtic Irishman, thus Macland, Ireland.

1674		Hogan-Moganides 19: Each one A Gallemauphrey Mermidon, Van Heer Mac Teige, Don Juan ap Morgan.
1674		Rochester ‘Tunbridge Wells’ in Works (1999) 51: Next after these a fulsome Irish Crew / Of Silly Macks were offer’d to my view.
c.1687		‘Mac O Bonniclabbero of Drogheda’ Bog Witticisms LXVII 70: A certain Mac-land-man meeting a Woman that Sold Lace and Linnen, took hold of her Box of Goods.
1690		‘Teague’ Teagueland Jests I 10: A certain Mac-lander had listed himself in the Spanish Army [ibid.] 41: Mac goes according to his masters order and receives the forty Pounds.
1690		‘Teague’ Teagueland Jests I 42: Why Mac, where would you have run with it? Quoth Mac, O mee Shoul! into mine own Country, in Macland.
1827		P. Cunningham New South Wales II 242: Many a Mac in your town, if only he knew what the situation of a convict was, would not be long in following my example!
c.1940–5		‘Myles na gCopaleen’ Best of Myles (1968) 289: Are you mad, Mac? Are you in your right mind man?
1978		Maledicta II:1+2 (Summer/Winter) 162: Mac Any Scotsman or Irishman, or person of Scots or Irish ancestry. From the prefix Mc- or Mac- attached to many Scottish and Irish surnames, meaning originally ‘son of’.

2. a male Scot.

1730		Fielding Tom Thumb I iii: Ireland her O’s, her Mac’s let Scotland boast .
1839		Crim.-Con. Gaz. 2 Mar.69/1: Many Scotchmen hab emigrate to dis refuge for de destitute [...] if him tell de crier ob de prison to [...] call Mac, Mac, him had a head pop out of ebbery room.
1902		A.G. Hales McGlusky 7: ‘Mac’ was deeply religious in a way of his own.
1917		K.F. Cowing letter Dear Folks at Home (1919) 10: ‘Mac’ [...] is as proud as any leatherneck I’ve ever met over his being in the United States Marine Corps.
1929		(con. 1916) F. Manning Her Privates We (1986) 140: ’Ere we are, ’ere we are, ’ere we are again, / Pat and Mac, and Tommy and jack, and Joe!
1933		M. Marshall Tramp-Royal on the Toby 174: Class war in the grubber, Mac; can you beat it!
1978		see sense 1.
1987		I. Rankin Knots and Crosses (1998) 23: I know everything, Mac.
1996		Penguin Bk of More Aus. Jokes 342: This bloke’s from Edinburgh. He’s called Mack the Scot.

3. (US) a general term of greeting with no specific ref. to Scottish or Irish men implied.

1908		‘O. Henry’ ‘The Ethics of Pig’ in Gentle Grafter (1915) 236: Hey, Mac [...] Nothing wrong with the world-wide this morning, is there?
1929		H.W. Brecht Downfall 155: Thanks, mack.
1934		R. Sale ‘A Nose for News’ in Goulart (1967) 207: I caught a cab, said: ‘Headquarters, Mac.’.
1937		E. Anderson Thieves Like Us (1999) 175: You got a dime, Mack, for an old boy.
1948		(con. 1944) N. Mailer Naked and Dead 7: They call me Mac. The name’s unimportant.
1955		B. Schulberg On the Waterfront (1964) 193: Hit me again, Mac.
1957		(con. WWII) ‘Weldon Hill’ Onionhead (1958) 60: [of medicine] A petty officer wordlessly gave him a glass full of liquid salts [...] ‘Down the hatch, mack’.
1962		F. Norman Guntz 134: Sorry Mac it ain’t my table.
1968		(con. 1930s) J. Healy Death of an Irish Town 42: So what’s a hero today, mack?
1969		C. Sellers Where Have All the Soldiers Gone 42: ‘Take it easy, mac; those holes get infected’.
1974		D. Goines Never Die Alone 29: What did you say, mac?
1976		H. Selby Jr Demon (1979) 24: I’d feel funny calling you buddy or Mack.
1981		G.V. Higgins Rat on Fire (1982) 133: Hey [...] why’ncha leave the kid alone again, all right, Mac?
1992		K. Lette Llama Parlour 38: Sure, mack. Get real. You’re talkin’ to women here.
1998		J. O’Connor Salesman 106: You needn’t bother saying that to me, Mac.
2011		‘Jack Tunney’ Cutman [ebook] Yeah, mac, you can do something for us. You can move your boat.