Green’s Dictionary of Slang

1. to inform (against).

c.1850		‘Bates’ Farm’ in Farmer & Henley Sl. and Its Analogues I (1890) 142/1: I mean to crack a crib to-night, but pals don’t ‘crack on me’.
1968		‘Hy Lit’ Hy Lit’s Unbelievable Dict. of Hip Words 10: crack on – Squeal, drop the dime, fink, to tell on somebody; the act of a real fink.

2. to talk at length, to criticize.

1869		C.G. Leland ‘Breitmann in Politics’ Hans Breitmann About Town 37: ‘Dis is very vine,’ says Misder Twine, ‘Vot here you indroduce: / Mit your bermission, I’ll grack on / Mit my shdory of de coose.’.
1888		Kipling ‘The Madness of Private Ortheris’ Plain Tales from the Hills (1890) 269: What’s the use of cracking-on for nothing?
1890		Kipling ‘Black Jack’ Soldiers Three (1907) 101: We shtart the divil an’ all av a shine — laughin’ an’ crackin’ on an’ t’rowin’ our boots about.
1897		W.S. Maugham Liza of Lambeth (1966) 43: ‘I don’t ’old with such foolishness. It’s wiste of money ter me,’ she said. ‘Na then, don’t crack on, old tart,’ remarked her husband.
1913		Truth (Sydney) 25 May 11/3: So I’m werry much discreet, & / Though I do crack on to you.

3. to tell tales, to boast.

1892		Kipling ‘The Young British Soldier’ in Barrack-Room Ballads (1893) 187: Don’t grouse like a woman nor crack on nor blind / Be handy and civil.
1901		A. Binstead More Gal’s Gossip 68: To hear Minnie crack on about the men who are ‘dead gone’ on her you really would think she was the only bit of cake in the pantry.
1940		F. Sargeson ‘A Good Boy’ in A Man And His Wife (1944) 73: She cracked on that I was the only fellow she was going with but I found her out.
1968		Punch 11 Sept. iv: [advert] There she was cracking on about having colour T.V.
2012		D. O’Donnell Locked Ward (2013) 5: I always thought Magnus was a lot less daft than he cracked on to be.

4. (US, also crack, crack at) to disparage, to attack verbally.

1913		H.G. Van Campen ‘Life on Broadway’ in McClure’s Mag. Mar. 35/2: It shows what women are. I ain’t crackin’ at you personally.
1935		Z.N. Hurston Mules and Men (1995) 32: ‘Whut you always crackin’ me for?’ Gene wanted to know. ‘Ah ain’t a bit blacker than you.’.
1978		R. Price Ladies’ Man (1985) 8: If we started cracking on each other with truths at this point we would inevitably get to the bottom truth.
1981		W.D. Myers Hoops 48: [T]hey were winning easy. [...] Even the referees were cracking on us.
1982		Eble Campus Sl. Fall 2: crack – to embarrass or humiliate someone, especially in public.
1994		N. McCall Makes Me Wanna Holler (1995) 25: To avoid being cracked on, you had to learn what was hip [Ibid.] 119: He’d cracked hard on my lady.
1997		(con. 1970s) G. Pelecanos King Suckerman (1998) 90: Not that Ronald would even think about cracking on Cooper about being a sissy.
2000		G. Pelecanos Shame the Devil 153: He never was all that good with his hands, anyway. Charles always used to crack on him about that.
2008		Simon & Burns ‘Get Some’ Generation Kill ep. 1 [TV script] Beaners ’re crackin’ on your people too.
2012		G. Pelecanos (con. 1972) What It Was 59: No one cracked on Frank, a local with a work ethic.

5. to reveal, to talk about.

1919		V.J. Marshall World of Living Dead (1969) 103: Perhaps [the war] was over orlready, an’ they hand’t cracked on a word about it.
1974		G.F. Newman You Flash Bastard 156: But he felt that even Terry Sneed was a little apprehensive about the way things stood now, only he didn’t crack on.
1984		P. Barker Blow Your House Down 22: He kept most of the money back, and he’d never crack on what he earned.

6. to pretend.

1962		H. Livings Nil Carborundum (1963) Act I: They kept cracking on they’d lost the key, but in the end they had to give in.
1977		(con. 1950) J. Rosenthal Spend, Spend, Spend Scene 13: Cracking on it’s a scarf. Lipstick. Lads. You’re going the right way, aren’t you?
1982		P. Barker Union Street 178: Sometimes I thinks she’s a lot more with it than she cracks on.
2005		P. Howard Curious Incident of the Dog in the Nightdress 20: The stud muffin here’s cracking on to be totally interested.

7. (also crack onto) of a man, to flirt; to attempt the verbal stages of seduction.

1969		A. Buzo Rooted I iii: He was always a bit scared of girls. Never seemed to have the knack of cracking on.
1979		Lette & Carey Puberty Blues 99: I wanted something new and he’d been cracking on to me.
1982		Eble Campus Sl. Fall 1: crack – to try to court or woo: The guy tried to crack on the new girl.
1986		C. Bowles G’DAY 7: Shane and his friend Macka are going to the disco. [...] They are hoping to crack on to some tarts and do a bit of good for themselves.
1989		(con. 1982–6) T. Williams Cocaine Kids (1990) 87: When I crack on a female ‘how you livin?’ she got to respond to me in the positive, or I don’t waste my time.
1990		T. Winton Human Torpedo 78: Nah, Lockie wouldn’t crack onto a snob.
2002		S. Maloney Something Fishy (2006) 70: The randy desperation which led me to crack on to a half-sloshed twenty-four-year-old.
2004		L. Redhead Peepshow [ebook] The men were too busy [...] to bother cracking onto a couple of off-duty strippers.
2014		me-stepmums-too-fuckin-hot-mate at www.fakku.net 🌐 Crack on to some other rando that wasn’t you [...] as if.
2019		Times Times2 3 June 3/1: Love Island: a handy glossary Crack on To start a romantic relationship with someone.

8. to notice.

1973

T. Lewis Billy Rags [ebook] The only person who’d cracked on to my being in the doorway was Terry Beckley.

9. (N.Z.) to bore.

2003

McGill Reed Dict. of N.Z. Sl.

10. see crack v.³ (1)