Green’s Dictionary of Slang

1. to brand a company or fellow worker as a strike-breaker.

1806		in J.R. Commons Documentary Hist. of Amer. Industrial Society III 73: I was liable to be scabb’d. [...] If I did not join the body, no man would set upon the seat where I worked; [...] they would neither board or work where I was unless I joined [DA].
1888		Montreal Daily Herald 21 Feb. 1/5: Engineers and others who refused to hoist or handle coal during the late effort to ‘scab’ the collieries [OED].
1922		F.B. Young Pilgrim’s Rest 409: [The rioting strikers] went away, saying they’d come back again and scab us to-night [OED].

2. (also scab on someone/something) to break a strike, refuse to join a union or any form of mass action; ext. to ‘letting down the side’ in non-work contexts.

1806		in J.R. Commons Documentary Hist. of Amer. Industrial Society III 75: Their business was to watch the Jews that they did not scab it [DA].
1887		Northampton Mercury 1 Oct. 8/3: There was another man [...] who had ‘scabbed’ every shop he had the opportunity of ‘scabbing’.
1897		Worker (Brisbane) 4 Sept. 8/3: But ‘going in’ in time of strike on any terms, to grab, / He doesn’t know as blacklegging but simply calls it ‘scab’.
1898		Scribner’s Mag. Oct. 445/2: I won’t scab any man’s job [DA].
1902		‘Strike Breaker’s Lament’ in Lingenfelter et al. Songs of the Amer. West (1968) 175: He boxed the stiff and shipped him, as fast as he could go, / To the land of scabbing miners in Joplin, Joplin, Mo.
1904		Sydney Sportsman (Surry Hills, NSW) 19 Oct. 1/3: They wanted no blacklegs, and if any member did ‘scab’ [...] he might rest assured there would be no forgiveness.
1912		‘Casy Jones, Union Scab’ in Lingenfelter et al. Songs of the Amer. West (1968) 83: That’s what you get for scabbing on the S.P. line.
1914		Sport (Adelaide) 17 July 4/3: Slops was seen purchasing a new colour at W.F.W.’s [...] Why scab on the washerwoman, Slops?
1919		Morgan City Dly Rev. (LA) 16 June 1/4: Strikers are patroling the treets [...] carrying placards reading ‘Don’t Scab!’.
1928		E. Pound letter 21 Nov. in Paige (1971) 220: They won’t be scabbing the printers, as they wd. be doing work not done by printers, i.e. not taking work from them.
1930		‘Dean Stiff’ Milk and Honey Route 113: It may be that they are shipping you out for strike-breaking duty [...] you may be sure they are roping in the yeggs and the bums to go out on scabbing jobs.
1935		Peters & Sklar Stevedore II i: lem.: What do you want them to do? Stick with us or scab for Walcott? al.: They’ll scab on you anyway.
1938		J. Devanny Paradise Flow 223: If I had scabbed in Australia I wouldn’t live here. I’d go to a country where nobody would know me.
1941		K. Tennant Battlers 237: You ask a man not to work, and then one of your own mates goes out and gets a job scabbing.
1951		(con. 1941) E. Lambert Twenty Thousand Thieves 188: There yer are [...] They’re scabbin’ already.
1953		I. Hamilton Till Human Voices Wake Us 171: When the pressure really came on, there were precious few individuals who wouldn’t scab.
1953		W. Brown Monkey On My Back (1954) 213: He also had trouble with the unions, once having been beaten up for scabbing.
1958		(con. 1940s) B. Behan Borstal Boy 302: Holy Joe, that scabbed it, who wouldn’t join the Society.
1961		R.S. Close With Hooves of Brass 118: ‘Well, we don’t want to scab on Ziff,’ Stitchem said.
1963		W.H. Pearson Coal Flat 138: Doing overtime. Scabbing on the union.
1971		F.J. Hardy Outcasts of Foolgarah (1975) 87: You happen to have pinched my job [...] you’re scabbing.
1973		(con. 1930s) F. Huelin ‘Keep Moving’ 58: Well! You didn’t scab [...] And if yous had some working-class principles then, why don’t you try an’ do us a bit of good now?
1982		Lowenstein & Hills Under Hook 60: They tell of a Port Melbourne man who, having scabbed in 1928, never left his house again.

3. to take a job without belonging to the relevant union.

1924		‘Digit’ Confessions of a Twentieth Century Hobo 109: Union wages were six dollars a day, but as the union was broke and open shop was the rule, we were not scabbing.
1956		N. Algren Walk on the Wild Side 85: Son, you aren’t implying you’d scab, would you?
1965		L. Haylen Big Red 8: If any of youse bastards hasn’t got his A.W.U. ticket, now’s the time to get it [...] You can’t scab it.
1994		(con. 1920s) K.C. Kearns Dublin Tenement Life 88: One of our next door neighbours worked on the docks and he went down (during the 1920s strike) and took me father’s job – he scabbed it.

4. (N.Z. prison) of an inmate, to curry favour with the authorities.

1982

G. Newbold Big Huey 233: Scabbing is something which can’t be tolerated.

5. (Aus.) to cadge, to scrounge.

1986		T. Winton That Eye, The Sky 69: In the carry basket was some clothes he said he scabbed from Mrs Musworth at the pub.
1998		P. Doyle (con. late 1950s) Amaze Your Friends (2019) 149: I scabbed as many free meals as I could.
2010		L. Redhead Thrill City [ebook] Couldn’t have been to scab cash because I don’t have any.