Green’s Dictionary of Slang

1. the end, the climax, esp. a decisive conclusion, an absolute end.

1896		F. Hutcheson Barkeep Stories 112: ‘An’ de blow-off is always de same. Neider wan o’ dem ever wins dc argument’.
1911		G. Bronson-Howard Enemy to Society 294: They had th’ statements he’d nailed [...], they’d publish th’ whole story in th’ papers less’n they let Steve take a walk and let that be th’ blow-off!
1915		Van Loan ‘The Extra Man’ in Buck Parvin 27: For the blow-off Myrtle’s lion-taming stunt goes wrong.
1916		J. Lait ‘Canada Kid’ in Beef, Iron and Wine (1917) 155: While he was out his mother died, an’ he told me it was a swell blow-off, wit’ a church an’ weepin’ neighbours an’ everything.
1920		Ade Hand-made Fables 96: [He was] all packed and was ready to Yo-Heave-Ho, when the Blow-Off came.
1930		J. Lait Put on the Spot 171: You ain’t got a decent blowoff comin’ to you. But I’ll give youse—all o’ youse—time to pray.
1940		W.R. Burnett High Sierra in Four Novels (1984) 343: I’m going back to L.A. in a couple of days if the blow-off don’t come.
1947		B. Schulberg Harder They Fall (1971) 242: So this is the . . . blow-off?
1952		Lait & Mortimer USA Confidential 194: It is in this field that the big blowoff which will rock Texas to the foundations of its spurious civilization will come.
1991		O.D. Brooks Legs 40: The blow-off came when the door was slammed shut on the terrified bastard’s ass.

2. (US Und.) the final stage of a confidence game, when the victim, now robbed, is quickly sent on his way; thus any form of dismissal.

1905		Little Falls Herald (MN) 31 Mar. 3/3: How to Operate the Shell Game with Profit [...] If the ‘gee’ springs a fat roll, tip the ollie a finif to vamp until the blow off.
1909		H. Green Mr. Jackson 290: The blowoff’s gettin’ nearer every minute, soon’s Frisco gits tired of foolin’ around with this bunch.
1910		D. Runyon ‘Art of High Grading’ in Pittsburgh Post-Gaz. (PA) Sun. Mag. 2 Jan. 8/1: Kewanee kept me around for about a week until the blowoff.
1924		D. Hammett ‘Nightmare Town’ in Nightmare Town (2001) 33: Things are about ripe for the blow-off.
1937		(con. 1905–25) E.H. Sutherland Professional Thief (1956) 121: A man who had just been beaten by a con mob [...] was given the blowoff and was carrying out the instructions of the inside man so enthusiastially that he actually ran towards the railway station.
1940		D. Maurer Big Con 156: The secret to long immunity from arrest is a properly staged blow-off.
1940		C. Rawson Headless Lady (1987) 46: Probably waiting to work the connection after the blow-off.
1947		F. Brown Fabulous Clipjoint (1949) 119: ‘What’s a blow?’ ‘Short for blow-off. It’s a show for inside money, usually inside a freak show. I mean, say, you pay two bits to get into the freak show and the spieler takes you around the platforms and then starts an inside bally for another two bits or more to see a special show on the inside, down at one end of the top.’.
1951		D. Dressler Parole Chief 238: We are ready for ‘the blowoff.’.
1953		A.J. Liebling Honest Rainmaker 32: Then came the Blow Off. The jolly Captain came to a sudden and drastic decision: ‘Enough is enough.’.
1963		A.S. Fleischman Venetian Blonde (2006) 173: I didn’t believe [...] Maggie was going to vut me in for more than peanuts. At the blowoff she might be hard to find.
2001		‘Randy Everhard’ Tattoo of a Naked Lady 20: We had to give him the blow-off but quick.
2016		T. Robinson Rough Trade [ebook] I was giving him the royal blow-off.

3. the very last tolerable happening in a series, ‘the last straw’.

1916		J. Lait Beef, Iron and Wine (2008) 272: Well, that’s the blow-off. Here’s curtains for you, Gene the Greek.
1929		C. Coe Hooch! 95: Just as soon as they do, Swinnerton – well, that’ll be the blow-off.
1938		J.E. Hoover Persons in Hiding 87: ‘This is the blow-off,’ he mumbled. ‘They’ve got Boss McLaughlon. We’ve all got to leave town.’.
1943		I. Wolfert Tucker’s People (1944) 27: Now he thought it was funny a five-dollar bet with Shortie should come to be the blowoff when there had been so many other more important things.
1959		W. Burroughs Naked Lunch (1968) 31: Well, this rumble in the operating room [...] was the blow off.

4. (US Und.) the act of commiting a robbery or burglary.

1928

J. Callahan Man’s Grim Justice 47: Not one in a thousand crooks gets caught doing the job. The pinch comes after the blowoff.

5. (US Und.) the detection or discovery of a criminal act.

1929		Hostetter & Beesley It’s a Racket! 220: blow off—exposure, detection, discovery.
1961		W.R. Burnett Round the Clock at Volari’s 57: In fact, if Al [...] didn’t keep his head this might turn into the big blow-off that the Reformers had been looking for ever since they took office.

6. (US Und.) a jail-break.

1935

A.J. Pollock Und. Speaks 10/1: Blow off, a prison break.

7. (US black) a shooting.

1931

A. Bontemps God Sends Sun. 85: It then occured to Augie that the hour was a bit early for a blow-off; there were too many people about.

8. (US) in sporting use the money that is made by concessions as the fans are leaving the ballpark.

1962

B. Veeck Veeck — as in Wreck 119: If the home team wins, you will do twice as much business during the concession blowoff; that is, in the amount of money the customers spend as they are leaving the park. Being happy, they are twice as willing to leave some money behind.

9. a sudden or casual departure.

2003

McGill Reed Dict. of N.Z. Sl. 25: blow off [...] Sudden or casual departure.