Green’s Dictionary of Slang

a mild, euph. oath; lit. ‘God’s truth!’ (cf. gawdstruth! excl.).

1883		J. Greenwood Tag, Rag & Co. 178: Oh, struth! and all I got left of it is this here seven-pence-ha’penny.
1888		Sporting Times 8 Sept. n.p.: ‘Strewth!’ cried Joe Capp, ‘Who’s bee washing the dishcloths?’.
1892		Kipling ‘Cells’ in Barrack-Room Ballads (1893) 162: Mad drunk and resisting the Guard — / ’Strewth, but I socked it them hard!
1898		Binstead & Wells Pink ’Un and Pelican 28: ‘A’mighty oh and streuth!’ (his invariable oath).
1898		Coolgardie Miner (WA) 24 Dec. 6/5: He let out a single ‘strewth,’ jumped six feet or thereabouts in the air, and lit out for the street.
1902		Bulletin (Sydney) 29 Nov. 31/1: ‘A nice put-up job.’ / ‘’Struth, no! Didn’t you see Mick the Mule?’ / ‘Dicken!’ / ‘Straight wire! He’s just out of quod, and he tried a Joe Rail on me for some beans.’.
1906		E. Dyson Fact’ry ’Ands 4: ‘I’ll word ’em when they pass again,’ he says, ’n’ struth he done it.
1906		Marvel 21 Apr. 345: I’m fond o’ funerals, I am, ’struth.
1911		L. Stone Jonah 60: ’Strewth! I niver thought o’ that.
1916		R. Service ‘My Prisoner’ in Rhymes of a Red Cross Man 120: ’Struth! But ’e was sich a ’andsome bloke.
1922		Eve. Post (Wellington) 10 May 3/8: ‘Struth,’ the ’Varsity extravaganza [is] to be presented this evening at the Grand Opera House.
1923		Sun. Times (Perth) 11 Feb. 1s/5: A series of punches that drew forth from the spectators a chorus of ‘Gauds!’ [and] ‘Struths!’.
1924		(con. WWI) A.G. Pretty Gloss. Sl. [...] in the A.I.F. 1921–1924 (rev. t/s) n.p.: struth. An exclamation of surprise.
1929		J.B. Priestley Good Companions 136: ’Strewth, you ought to ’ave ’eard ’im.
1932		(con. WWI) L. Mann Flesh in Armour 146: ‘Gawd struth, she’s a yid. You’ll have to write to her, Ikey’.
1934		J. Franklyn This Gutter Life 49: I know it’s a small place, and pretty crowded, but ’s’truth!
1938		F. Durbridge Send for Paul Temple (1992) 40: Strewth, I didn’t ’alf turn queer!
1939		K. Tennant Foveaux 59: ’Struth, it’s cold sitting on this step.
1940		F. Sargeson ‘A Pair of Socks’ in A Man And His Wife (1944) 64: Struth he was dag, Bill was.
1941		K. Tennant Battlers 114: ‘Strufe, Harry,’ she concluded, ‘I dunno what, wiv one fing an’ anover . . .’ She broke off dejectedly. ‘It’s bloody awful.’ [Ibid.] 192: Stroof! but I must be cartin’ about a ton of these flies.
1942		A. Christie Body in the Library (1959) 22: ‘Strewth!’ Blake stared at him.
1952		C. Harris Death of a Barrow Boy 9: Strewth! Return of the prodigal!
1953		T.A.G. Hungerford Riverslake 181: Struth, what a road!
1963–74		B. Humphries Barry McKenzie [comic strip] in Complete Barry McKenzie (1988) 51: Struth, it’s Kevin alright.
1964		J. Orton Entertaining Mr Sloane Act I: How long is it? / Twenty years / ’Strewth!
1974		D. Ireland Burn 11: Struth! You sound as if you like this place.
1981		A. Payne ‘You Need Hands’ Minder [TV script] 5: Mr Daley? Strewth.
1982		J. Andersen Winners Can Laugh 13: Struth, what’s ’e doin’ ’ere?
1989		T. Blacker Fixx 85: ‘Streuth!’ said Reggie.
1996		J. Byrell Lairs, Urgers & Coat-Tuggers 306: ‘Struth, they hit us from everywhere with everything they had’.
1999		Guardian G2 10 June 9: ’Struth! Smells like a cut price sewage farm!
1999		Indep. on Sun. Rev. 25 July 7: Strewth! One hundred and eighty-one wholly underwhelming and vacuous words.
2001		J. Bryant Real Aussies Drive Utes II 103: ‘Strewth, Ruth!’ I exclaimed, bouncing out of my chair.
2003		Guardian G2 5 June 3: Strewth, this bloke’s been busier than a cat burying shit.
2010		Sun. Times Sport 19 Dec. 25/4: [headline] Strewth, he’s bowled another Sheila over.
2015		N. Cummins Tales of the Honey Badger [ebook] [pic. caption] The nomads aren’t shy on the vodka either...strewth!