Green’s Dictionary of Slang

1. (US black) to strike a pose reflecting one’s image as a hipster n. and to show off the line of one’s zoot suit n.

1965

(con. 1940s) Malcolm X Autobiog. (1968) 135: [I] posed the way ‘hipsters’ wearing their zoots would ‘cool it’ — hat angled, knees drawn close together, feet wide apart, both index fingers jabbed towards the floor. The long coat and swinging chain and Punjab pants were much more dramatic if you stood that way.

2. (orig. US) to leave.

1952		Hal Ellson Golden Spike 139: Cool it, they’re coming fast!
1967–8		Baker et al. CUSS.

3. (US) to arrange, to fix something, to protect from the authorities.

1957

J. Blake letter 15 July in Joint (1972) 104: Willie told me he would cool it for me if I stayed out after Lockup.

4. (orig. US black) to calm down, to relax; often as imper. cool it!

1952		Hal Ellson Golden Spike 19: ‘Cool it, man,’ he shouted.
1961		T. Taylor Baron’s Court All Change (2011) 15: I decided to cool it in the dining-room [...] putting [on] a very swinging disc of the Bird’s.
1966		H.S. Thompson Hell’s Angels (1967) 47: Man, we’d be sitting over there in the bar [...] just coolin’ it around the pool table with a few beers.
1970		T. Southern Blue Movie (1974) 221: We’re just sort of cooling it.
1977		E. Bunker Animal Factory 28: ‘Cool it’, he said, ‘You forget who’s the lieutenant today.’.
1988		Beano Comic Library Special No. 12 4: Hey! Cool it, Harry.
1992		R.G. Barrett Davo’s Little Something 50: He was sweet there, no need to worry abotu that, but it was best to cool it.
1999		Indep. 6 Nov. 3: She wanted to say to Tony Blair ‘Cool it, buddy boy’.
2000		P. Roth Human Stain 220: ‘Cool it,’ Louie says.
2015		I. Welsh Decent Ride 179: Evan took [bullying] to extremes. Ah even telt um tae fuckin cool it a few times.
2018		(con. 1963) L. Berney November Road 29: Guidry was walking too fast. Cool it, brother.
2022		A. Kirzman Giuliani 30: Judge Robert Carter [...] ordering Giuliani to cool it when he went over the top.

5. (orig. US black, also cool) to stop, to cease from an action.

c.1953		Babs Gonzales ‘Manhattan Fable’ 🎵 He figured that he’d cool until his greens was long enough for him to sound her.
1953		E. Hunter ‘Vicious Circle’ in Jungle Kids (1967) 31: ‘Hey, man [...] get off that [i.e. indiscreet speech]. Cool it fast.’.
1961		T. Taylor Baron’s Court All Change (2011) 125: ‘Perhaps we’d better cool it for a few days,’ I suggested.
1961		M. Braly Felony Tank (1962) 102: The usher tapped Agnes. ‘You better cool it.’.
1975		E. Torres Carlito’s Way 77: Cool it, here he comes.
1980		E. Folb Runnin’ Down Some Lines 3: Chump better cool it.
2005		Mad mag. July 37: Dad, maybe we should cool it with the lawsuits.

6. (US) to die; thus cooling board, the death bed.

1925		Odum & Johnson Negro and His Songs (1964) 205: Eddy Jones call for the coolin’-board, / Lawdy, lawdy, lawd! [Ibid.] 206: The ‘coolin’-board’ is the death-bed, and is a common expression used to signify that one’s time is at an end, that is, when he is to be on the ‘coolin’-board’.
1967		M. Braly On the Yard (2002) 275: ‘How is he?’ ‘He’s cooled it.’.
1971		(con. 1920s) G.M. Foster Pops Foster 66: They’d lay the dead man out in the parlor on what was called a ‘coolin’ board’.

7. to draw back from, to cease relating to.

1968		New Yorker 27 Jan. 108: He like Dean Martin, only needs to play on his public image — to cool it.
1977		C. McFadden Serial 59: I’ve got a lot of tension about the divorce [...] So cool it with Vivian, okay?
1982		H. Beaton Outside In I i: You’da thought she woulda cooled it for a bit. ’Till the heat was off.
2008		J. Lansdale Leather Maiden 125: ‘So, after you cooled it with her?’ [...] ‘We’d see her at school’.