Green’s Dictionary of Slang

1. (UK Und.) to discover, to pursue.

c.1790		‘The St Giles’s Flash Man’ in Busy Bee II 122: For we have flagg’d a precious go, / And queer’d the flats at Thrum’s E.O. , / Every night in Titmouse Row.
1840		in Facetious Songster in Spedding & Watt (eds) Bawdy Songbooks (2011) III 250: [as c.1790].

2. to refuse service to someone in a bar, to stop someone drinking; often as flagging, refusing service.

1891		Salina Dly Republican (KS) 25 Sept. 3/2: Flagged — Person who has been refused more drink by a scornful bartender.
1983		P. Dexter Gods Pocket 223: ‘If you bring patriotic into it, you're flagged [...] You start talking about niggers and America here tonight, I swear you won’t get another drink till winter’.
2003		‘YoMomma’ Diary 29 Jun. at Diaryland.com 🌐 So she takes the beer, right out of my hand and she’s like, ‘youre done’ and I’m like ‘youre flagging me?’ so I grabbed another beer and she took that from me. I said ‘you cant flag me’ so she was being a bitch so I left.

3. (US) to signal an interest in someone in anticipation of romantic or sexual involvement; to accost; thus as n. the gesture that signifies attraction.

1896		Ade Artie (1963) 81: She did n’t want you to think that any Reub could go up and flag her.
1901		W. Irwin Love Sonnets of a Hoodlum V n.p.: Last night – ah! yesternight – I flagged my queen [...] I up and braced her, breezy as a gale.
1927		‘Jargon of the Und.’ in DN V 446: Flag, (1) To accost a prostitute.
1949		Monteleone Criminal Sl. (rev. edn).
1966		R. Giallombardo Gloss. in Study of a Women’s Prison 203: Flagging. Older inmate attempting to involve youthful inmate in homosexuality.
1972		B. Rodgers Queens’ Vernacular.

4. (US tramp) to reject, to turn someone away.

1896		F. Hutcheson Barkeep Stories 10: ‘[He] starts off like he was goin’ t’ spiel his troubles to me, but I flags him an’ tells him I’m overloaded wid de meself’.
1905		H. Green Actors’ Boarding House (1906) 108: Oh, I had to flag him!
1912		Van Loan ‘Ten-Thousand-Dollar Arm’ in Ten-Thousand-Dollar Arm 25: Bruno flagged the Beau, and sent Belcher to the rescue.
1923		H.C. Witwer Fighting Blood 27: To be flagged from the party itself and then made to deliver their refreshments to the kitchen!
1930		‘Dean Stiff’ Milk and Honey Route 205: Flagged – It may mean to be driven out of town, to be turned down.
1943		R. Brister ‘Rock-a-Bye Booby’ in Ten Detective Aces Sept. 🌐 He tried to cut in on Tom and Linda. When she flagged him, he looked pretty suspicious about it.
1993		(1970s) K. Scott Monster (1994) 10: These fools have been [...] [h]ittin’ people up [...] flaggin’ and disrespectin’ every Crip in the world.

5. (gay) to attract a stranger with the eyes or with a slight gesture of the head.

1901		W. Irwin Love Sonnets of a Hoodlum XIII n.p.: She could flag some Handsome Hank and slope.
1941		G. Legman ‘Lang. of Homosexuality’ Appendix VII in Henry Sex Variants.
1965		Guild Dict. Homosexual Terms 16: flag (v.): A gesture or signal with the hands, eyes, head to a stranger to get him to speak; a first step in a ‘pickup’.

6. (US) to allow someone to pass by, esp. the intended victim of a pickpocket, to avoid.

1899		J. Flynt Tramping with Tramps 386: ‘Flagged’ is a word [...] used a great deal by pickpockets, and means that they have allowed a certain person whom they intended to victimize to pass on ummolested.
1921		P. & T. Casey Gay-cat 302: Flagged—when criminals permit a likely victim to go unmolested it is called ‘flagged’.
1931		Irwin Amer. Tramp and Und. Sl. 74: Flag.–To pass by; to ignore.

7. to dispose of; to ignore.

1909

H. Green Mr. Jackson 56: [Alonzo] allus was my middle name [...] but I flagged it. I don’t look like no Alonzo.

8. to attract someone’s attention.

1907		‘Hugh McHugh’ Beat It 87: We tried to flag her and talk her out of it.
1915		R. Lardner ‘Alibi Ike’ in Coll. Short Stories (1941) 49: He started out toward the desk, but we flagged him.
1930		‘Dean Stiff’ Milk and Honey Route 205: Flagged – [...] to be hailed by someone.
1935		R.L. Bellem ‘Beyond Justice’ in Spicy Detective Stories Nov. 🌐 I flagged him into silence.
1962		Ragen & Finston World’s Toughest Prison 799: flag – To accost or detain.
1963		A.S. Fleischman Venetian Blonde (2006) 157: Flag her in.

9. to stop doing something, to be quiet.

1911

S. Ford Torchy 2: ‘Ah, flag it!’ says I. ‘Do I look like I belonged in your class?’.

10. (US tramp) to beg.

1927

‘Jargon of the Und.’ in DN V x 446: Flag, (5) To beg. ‘I’m goin’ to flag the main drag’.

11. to leave; to travel.

1919		St Louis Post-Despatch (MO) 16 Jan. 25/2: Then a bunch of hick bulls lam out after you and you flag it for here.
1935		J. Conroy World to Win 209: If you don’t want a busted head, flag out of here.
1946		R.L. Bellem ‘Homicide Surprise’ in Speed Detective Feb. 🌐 Flag your diapers over here to Nick McLennan’s nest with great rapidity.