Green’s Dictionary of Slang

1. (orig. US, also bar cootie, fly) the habitual occupier of a bar, day in, day out.

[1875		Ottowa Free Trader (IL) 23 Oct. 1/3: The have on hand a large stock of first-class tobaco [...] Their special brands and ‘L&F and ‘Bar Fly’.
1896		Democrat Northwest (Napoleon, OH) 30 Apr. 2/2: The Ohio legislature [...] has increased the Dowe Tax [...] which gives a knock to the bar flies [...] for a while the bar-fly will probably be deprived of his occasional glass of beer.
1902		Rock Island Argus (IL) 26 June 5/3: Although the complaining witness offered to rpove that the defendant was a ‘free lunch fiend’ and a ‘bar fly’, his honor [...] dismissed the case.
1905		L.A. Times 16 July VII 7: [headline] SODA FOUNTAIN ‘BARFLIES’.
1912		Mt Sterling Advocate (KY) 3 July 7/2: Success in life bears a wide interpretation, rang from the free booze of the bar-fly to [etc.].
1920		A. Baer Two & Three 23 Feb. [synd. col.] The town [...] threatened to print a men containing the names of all the bar cooties in town.
1927		H. Asbury Gangs of N.Y. 53: An old hag known as Shakespeare was cut to pieces by a half-witted bar fly commonly called Frenchy.
1931		Ade Old-Time Saloon 105: He did the only thing he could do, and that was to encourage the spending proclivities of his own little group of bar-flies.
1946		S. Jackson Indiscreet Guide to Soho 105: An out-of-work all-in wrestler or just a barfly.
1949		N. Algren Man with the Golden Arm 43: The barflies who buzzed all day long between the curb and the bar.
1953		L. Uris Battle Cry (1964) 104: I was [...] trying to make time with a barfly.
1960		I. Freeman Out of the Burning (1961) 22: He treated all the barflies in Slim Jim’s Café.
1967		B. Crump Odd Spot of Bother 122: Of all the barflies, shout-dodgers [...] and other hopeful hangers-on.
1975		(con. 1900s) G. Swarthout Shootist 131: I planned to [...] buy a gun and some fancy clothes. Kill a few barflies and get me a reputation.
1984		C. Bukowski [Bk title] Barfly.
1997		A. Highcrest At Home on the Stroll 78: Have barflies inadvertently become cheerleaders for the drug trade?
2006		J. Ridley What Fire Cannot Burn 156: Hard drinkers – and the few flies in the bar at that hour were nothing but – stared at Tashjian.
2009		Observer Rev. 1 Jan. 25: Something of a barfly, he interweaves random encounters with eccentrics, strippers and KKK members.
2013		D. Whish-Wilson Zero at the Bone [ebook] Swann [...] did the barfly hunch; crumpled and bent, staring into the glass canoe.
2013		C.J. Ross ‘Three Days Ahead’ in ThugLit Nov.-Dec. [ebook] She was a nomadic bar fly.
2013		N. Knight ‘Not Even a Mouse’ in ThugLit Nov.-Dec. [ebook] Two flies grimaced over cans of Olympia.
2021		P. Papathanasiou Stoning 32: He had a fresh pint in his hand and was holding court with two fellow barflies.
2022		I. Fitzgerald Dirtbag, Massachusetts 95: [A] long dark room filled with hesher-looking barflies.

2. a prostitute who works from a bar; a woman (or gay man) frequenting bars to pick up men.

1957		C. MacInnes City of Spades (1964) 36: A look on her face like a bar-fly seeking everywhere hard for trade.
1958		E. Gilbert Vice Trap 103: She’s a barfly. She tricks sometimes for drinks.
1971		R.D. Pharr S.R.O. (1998) 16: Barflies. There’s no torure on earth worth than that feeling of loneliness you get after laying up with one of those.
1979		L. Bangs in Psychotic Reactions (1988) 294: So you let some barfly take you home, so what?
1986–7		Maledicta IX 149: The original argot of prostitution includes some words and phrases which have gained wider currency and some which have not […] bar fly.
2003		K. Cage Gayle 56/1: barfly n. someone who hangs about in bars in order to pick up a sexual partner.