Green’s Dictionary of Slang

1. (orig. US) to calm down; thus cooling-off adj.

1844		Central Jrnl (Kosciusko, MS) 6 Aug. 1/2: Take another horn, Simon, and cool off a little.
1853		S.F. Comm. Advertiser 9 Dec. 2/4: She defied his Honor and all his officers, [...] and giving assurance of a disposition never to ‘dry up,’ was carried down below to cool off [DA].
1898		Kipling ‘Stalky’ in Complete Stalky & Co. (1987) 20: Let ’em cool off. Golly! how that heifer danced!
1918		C.J. Dennis ‘Half A Man’ in Chisholm (1951) 104: An’ I ain’t cooled off yet before they’ve got / Me workin’ for ’em in this crooked plot.
1925		Wodehouse Carry on, Jeeves 17: I lit another cigarette and started for a stroll in the grounds, by way of cooling off.
1938		J.E. Hoover Persons in Hiding 14: The word passed from crook to crook that there was a ‘cooling-off joint’ in Tulsa where a criminal not only could get protection, but shrewd advice.
1938		W. Watson Miss Pettigrew Lives For A Day (2000) 146: I thought he might have cooled off before he came out.
1943		W. Guthrie Bound for Glory (1969) 122: Little too much noise there, buddy [...] Walk along with me till you cool off.
1953		J. Thompson Savage Night (1991) 99: Until Ruthie cooled off, I had to have some place to hang out.
1962		(con. 1940s) G. Mandel Wax Boom 289: Let’s both cool off, Sal.
1974		V.E. Smith Jones Men 98: I thought maybe he’d cooled off a little.
1982		Beano 2 Jan. 12: Until Dennis cools off a bit!
1997		(con. 1970s) G. Pelecanos King Suckerman (1998) 63: Let the boys I took it from cool off, then give it back.

2. (US) to be imprisoned.

1899–1900

C.L. Cullen Tales of the Ex-Tanks 301: George [...] is cooling off at the Harrison Street station.

3. (orig. US) to calm someone down.

1934		A. Halper Foundry 143: Now, here! If any of the boys get hot around the collar, I want you to cool ’em off.
1949		H. Wilson ‘I Was King of the Safecrackers’ in Hamilton Men of the Und. 139: I cooled him off, which was lucky.
1958		H.S. Thompson letter 19 May in Proud Highway (1997) 123: So I evaded his first charge and tried to cool him off.
1978		R. Caron Go-Boy! 112: When I started to bolt for the door he cooled me off.

4. (orig. US) to lose interest in; to cause to lose interest in.

1928		C. McKay Home to Harlem 114: As Jake was not brutally domineering, she cooled off from him perceptibly.
1949		‘Hal Ellson’ Duke 112: But that finished it. That cooled me off.
1958		C. Himes Real Cool Killers (1969) 14: Cooling off as quickly as a showgirl on a broke stud.
1963		B. Naughton Alfie I i: When a married bird gets too hot on, that’s the time to cool off.
1968		L. Wolf Voices from the Love Generation 133: The thing to do is to cool off dangerous drugs.
1999		Guardian G2 19 Oct. 4: The mortgage adviser appeared to cool off once he heard that Hege’s partner was not a man.

5. (orig. US) of a criminal, or persons involved in conflict, to lie low until the hue and cry has passed; thus cooling-off adj.

1937		E. Anderson Thieves Like Us (1999) 14: Cooling off at Dee’s and then going on down into Texas.
1947		C.S. Montanye ‘Frozen Stiff’ in Popular Detective Mar. 🌐 He found the ice cream company’s night watchman was an old pal cooling off there after a hot career.
1956		H. Ellison ‘Students of the Assassin’ in Deadly Streets (1983) 199: I’m hot, now. I have to cool off where the cops can’t find me.
1970		‘Red’ Rudensky Gonif 79: Honey, it’s the safest place on earth [...] You can stay here till spring if you want. But little Mert needs a little coolin’ off money, too.
1999		Guardian 13 July 20: ‘Please tell the attorney general that we have been cooling off for the past 350 years,’ Farmer told King.

6. to get rid of, to dismiss.

1940

J. Archibald ‘No Place Like Homicide’ in Popular Detective Apr. 🌐 Here I was getting warm on that bank messenger murder and they cool me off like that.

7. (orig. US) to become bored.

1952

Lait & Mortimer USA Confidential 54: He planned to remain in Israel until the committee ends or cools off.

8. (orig. US) of a gambler, to run out of luck.

1996

S. Frank Get Shorty [film script] Now you’re down to three-ten in the case. You must’ve cooled off quite a bit since you got here.

9. (US) to die.

1964

(con. 1917) S. Woodward Paper Tiger 73: [T]he Protestant undertakers [...] had to be checked three times a day [for a notable death]. The Catholics and Jews gave us no worry. They would call us the minute a prominent citizen cooled off.

10. (orig. US) of a stolen object, to be less hot adj. (5d)

1999

E. Bunker Mr Blue 290: I still had several partial batches of payroll checks. They had cooled off in the intervening months and it was easy to find people willing to go around cashing them. It was safe and lucrative.