Green’s Dictionary of Slang

1. an unaccompanied man at a dance or similar gathering.

1905		N. Davis Northerner 213: ‘No man not escorting a lady’—a stag, you know—could go upon the floor.
1927		‘J.M. Hall’ Anecdota Americana I 26: Overcome with emotion one of the stags shouted: ‘Fuck her hot!’.
1938		W. Winchell On Broadway 24 Nov. [synd. col.] Lillian and Dorothy Gish watching the stags gobble Society’s new glamor girl, Brenda Frazier.
1948		(con. 1944) N. Mailer Naked and Dead 344: The stags line up against the wall, chat cursorily with one another.
1961		M. Terry Old Liberty (1962) 204: She took the hand of one of the stags and made him dance with her.
1972		(con. 1916) G. Swarthout Tin Lizzie Troop (1978) 103: A stag at her debut [...] he had fallen head over heels with Olivia Darlington.
2012		D. O’Donnell Locked Ward (2013) 241: The kind of soft porn beloved of single stags.

2. any form of party or similar entertainment attended only by men.

1904		Brooklyn Eagle 28 May 3: The Myrtle Fishing Club will have a stag at Hurman Hub’s Park this evening [DA].
1912		N.Y. Times 17 Jan. 13: A searching investigation will be instituted by the police to discover the identity of persons engaged in the manufacture and production of indecent motion picture films. This industry [...] furnishes amusement at so-called ‘stags’ and smokers given by private clubs or individuals to which admission is by ‘invitation.’.
1932		J.T. Farrell ‘A Practical Joke’ in Short Stories (1937) 177: I don’t feel like going to the stag to drink and chew the fat.
1947		S. Lewis Kingsblood Royal (2001) 204: The Federal Club’s Auld Lang Syne Holiday Stag, holden annually between Christmas and New Year’s, which enabled the members [...] to bask in the clear sun of male conversation.
1958		R. Prather Scrambled Yeggs 22: A little poker, a stag now and then. No women.
1962		S. Longstreet Flesh Peddlers (1964) 179: G-stringed, tassel-nippled strippers for a ward heelers’ stag in Jersey City.
1987		R. Campbell Alice in La-La Land (1999) 203: Little stags that had been lame attempts to make friendships out of poker, beer, and dirty stories.
1994		I. Welsh ‘A Smart Cunt’ in Acid House 273: The day after the stag [...] I ran into Ted Malcolm.

3. (Aus./US) an unaccompanied woman (the suggestion being of her being a sex worker).

1895		Crowe Aus. Sl. Dict. 80: Stag, a woman without the gentler feelings of the heart.
1953		Cincinnati Enquirer (OH) 31 May 6/7: Campaign is launched on Newport ‘Stags’. Newport detectives [...] arrested eight women on charges of vagrancy in a drive to end frequenting of cafes by unescorted women.

4. (US) any form of men-only meeting.

2021

T. Swerdlow Straight Dope [ebook] [of Alcoholics Anonymous] [T]he meetings I do go to are mostly men’s stags.

5. see stag movie under stag adj.