Green’s Dictionary of Slang

1. (also good one) a dependable, trustworthy, admirable person or creature.

1800		‘Sung in Fontainbleau’ in Songster’s Companion 76: Oh! yes; John Bull’s a good’n.
1827		Egan Anecdotes of the Turf, the Chase etc. 19: While out-and-out good ones stand o’er him and weep.
1833		‘With My Cook So Fair’ in Lummy Chaunter 67: At the smell of her pudding, I sticks to her like a good ’un.
1835		‘A Hellebello In The Workhouse’ in Knowing Chaunter 24: Black Sarah, ’tis said, they their general made, / For to mill – she was naught but a good-un.
1846		Durivage & Burnham Stray Subjects (1848) 29: She’s a rum ’un to look at, but a good ’un to go.
1858		R.S. Surtees Ask Mamma 288: ‘A good ’un and nothin’ but a good ’un,’ replied the groom.
1861		H. Mayhew London Labour and London Poor III 7/2: The proprietor of the dog endeavoured to speak up for it, by declaring ‘it was a good ’un, and a very pretty performer’.
1879		G.R. Sims Dagonet Ballads 79: She’d worked like a good ’un, had Polly.
1883		J. Greenwood Tag, Rag & Co. 47: If you are a regular customer [...] you can git as good ’uns as a gal could wish to wear at fourpence a night.
1895		E. Pugh Street in Suburbia 43: She may turn art a reg’lar art an’ art ’ot ’un, or a right-darn good ’un.
1902		Bulletin Reciter 1880–1901 180: He’d a stable full of good ’uns.
1910		Marvel 15 Oct. 4: Jim Brooks [...] is a good ’un.
1923		Wodehouse Inimitable Jeeves 40: ‘Mais oui’ [...] shouted the Bandit Chief, backing me up like a good ’un.
1931		O. Strange Law O’ The Lariat 81: He’s a good ’un, Miss, an’ the boys know it.
1943		(con. 1850–60s) G.A. Little Malachi Horan Remembers 26: Swearing like good ones, they up with some harrow chains, and these they stretched across the road.
1956		J. Curtis Look Long Upon a Monkey 133: First you plug away like a good ’un against the brutes and now you want to sob and sigh all over them.
1962		F. Norman Guntz 11: Her name was Jess and she had always been a goodun.
1977		G.F. Newman Villain’s Tale 140: A fella in here told me about a brief, a right good ’un. [...] Go and see him, see if he’ll do a bit for me – he’s s’posed to be a bit near the mark.
1981		T. Wilkinson Down and Out 157: He’s a fucking Indian, but he’s a good ’un.
1999		K. Sampson Powder 91: She’s a good ’un.
2002		J. Cameron Hell on Hoe Street 27: Sharon was a good ’un, never let me down.

2. used similarly of an object or situation.

1823		Sydney Gaz. 30 Oct. 4/2: He likes to have a long yarn from the cove, who is sure to get a bit of tobacco if he tells Bill a good ’un.
1867		R. Whiteing Mr Sprouts, His Opinions 25: He rattled it out a good ’un.
1929		J.B. Priestley Good Companions 152: Biggish place – twenty or thirty boozers there – good ’uns some of ’em.
1936		(con. 1920s) Dos Passos Big Money in USA (1966) 758: What do you think of comin’ in the business, Charley ? It’s gettin’ to be a good ’un.
1941		G. Casey ‘Short Shift Saturday’ in Mann Coast to Coast 214: ‘Like to come to a party?’ [...] ‘She’ll be a good ’un,’ promised O’Connor.
1961		B. Crump Hang On a Minute, Mate (1963) 98: Lifted a couple of good’ns each and went back to Tony’s.

3. see good one n.