Green’s Dictionary of Slang

1. (orig. US) a wedding that is forced on the groom through his girlfriend’s (soon to be bride’s) pregnancy; thus shotgun baby n., the child that precipitates such a union; note extrapolated into a v. in cit. 1965.

1903		South Western Reporter 75 985: That was a shotgun wedding, and you will read something a good deal worse than that.
1907		Bradford Dly Teleg. 9 Mar. 2/8: A San Francisco ‘police judge’ prescribed the following [...] ceremony at ‘shot-gun weddings’.
1922		Eve. Teleg. (Angus, Scot.) 14 Feb. 2/1: ‘The Shotgun Wedding’ Century Comedy in 2 Acts.
1927		(con. 1900s) S. Lewis Elmer Gantry 156: There were, in those parts and those days, not infrequent ceremonies known as ‘shotgun weddings’.
1931		Ade Old-Time Saloon 162: They raise Cain all of the time and yet, for some reason, there are fewer shot-gun marriages.
1932		(con. 1919) Dos Passos Nineteen Nineteen in USA (1966) 662: If Dad or Buster was here it would be a shotgun wedding.
1936		(con. 1830s–60s) ‘Miles Franklin’ All That Swagger 163: He paid his debts and withdrew to prepare for a shotgun marriage.
1939		D. Burley N.Y. Amsterdam News 10 June 16: That hospital medico who faces a shotgun wedding with a stuent nurse.
1938		X. Herbert Capricornia (1939) 179–80: But by Gawd there’ll be a weddin’, if it’s gotter be a shotgun one!
1940		‘Digg Mee’ ‘Observation Post’ in N.Y. Age 7 Dec. 10/5: What is a ‘Shot Gun’ Wedding?
1949		A.B. Hollingshead Elmtown’s Youth (1975) 322: We acted as witnesses to two ‘shot-gun’ marriages.
1951		R. Leveridge Walk on the Water 266: He had been compelled to enlist in order to dodge what probably would have been a shotgun wedding.
1957		‘Weldon Hill’ Onionhead (1958) 307: ‘If marrying that bag is a shotgun necessity...’.
1959		Hays Dly News (KS) 15 June 10/1: A major aspect of the sharp upswing in teen-age sex activity is the shotgun marriage.
1964		P. Highsmith Two Faces of January (1988) 112: Agnes, he said, got married at seventeen. A shotgun wedding.
1965		L. Dunne Goodbye to The Hill (1966) 142: It would have killed Ma, to see me shotgunned into a wedding.
1968		G. Slatter Pagan Game (1969) 109: Everybody knew that his own wedding had been a shotgun job.
1968		A. Burgess Enderby Outside in Complete Enderby (2002) 312: Easy Walker had given Enderby [...] ‘The Ballad of Red Mick the Prancerprigger’, ‘The Shotgun Wedding of Tom Dodge’ [etc.].
1970		D. Ponicsan Last Detail 59: I heard it was a shotgun wedding.
1981		G. Young Slow Boats to China (1983) 240: It wasn’t a shotgun wedding so much as a popgun wedding.
1987		(con. 1920s) L. Redmond Emerald Square 50: Except when it was a ‘shotgunner’, many of the girls were virgins.
1988		S. Gordon Under the Harrow 88: They’re all married; the youngest was eighteen (a shotgun marriage).
1989		J. Hobbs Thoughts in a Makeshift Mortuary 136: Rose had been able to fling ‘shotgun baby’ at her mother.
2001		A. Sillitoe Birthday 216: I got married to Pauline because she was pregnant. A shotgun wedding, though no one needed to point the barrel at me.
2014		Democrat & Chron. (Rochester, NY) 26 Apr. B2/4: Birth records [...] from 1990 to 2012, show that althought shotgun marriage has declined, it is not obsolete.
2015		L. McInerney Glorious Heresies 80: Well, the first thing I did was arrange a shotgun wedding in my head.

2. (also shotgun alliance) fig. use of sense 1.

1959		(con. 1900-29) L. Katcher Big Bankroll 78: Becker became [Rosenthal’s] partner in the game at the Hesper Club. The shotgun alliance was a most unhappy one.
2008		Metro (L) 19 Sept. 7: Mr Daniels rejected accusations that the takeover represented a shotgun marriage between the companies.