Green’s Dictionary of Slang

to challenge, usu. preparatory to a fight; often in fig. use; thus squaring n., a challenge, usu. to a fight.

c.1790		‘Luke Caffrey’s Ghost’ in Limerick 2: He squar’d up to de two Bailies, tip’d one of dem a loving squeeze.
1823		‘Jon Bee’ Dict. of the Turf, the Ring, the Chase, etc. 164: To square, (ring) to present the fists for attack or defence.
1827		Exeter & Plymouth Gaz. 23 June 3/2: They once more ‘squared for the gripe’.
1827		P. Cunningham New South Wales II 22: A battle in the streets where the attitudes and squaring would have done honour to the London ring.
1840		West Kent Guardian 4 July 6/3: ‘Popish tongue,’ says she, squarrin’ at me.
1845		J. Lindridge Sixteen-String Jack 84: She picked herself up [...] and was already squaring up for another bout.
1849		Thackeray Pendennis I 380: He [...] staggered back, into what is called an attitude of self-defence, and in that position began the operation which is entitled ‘squaring’ at Policeman X.
1859		Wkly Advertiser (Montgomery, AL) 14 Sept. 3/1: Men are poor sinful creatures at best, and it is not to be expected in this vale of tears that they can ‘square up to the mark’.
1860		Hotten Dict. of Modern Sl. etc. (2nd edn) 225: ‘To square up to a man,’ to offer to fight him.
1866		Bury & Norwich Post 15 May 2/6: He flared up in an instant, and came squaring at old Wurst.
1876		C. Hindley Life and Adventures of a Cheap Jack 236: The stranger recovered from the shock of the fierce blow [...] was upon his pins, and, squaring up, let go his left.
1883		Portsmouth Eve. News 5 Apr. 2/6: They asked if he wanted to fight [...] squaring up to him, he knocked him down.
1899		J. Flynt Tramping with Tramps 376: Slim was not a coward, and got up and squared for the row.
1899		R. Whiteing No. 5 John Street 39: There warn’t no time to square up to ’im when I see the sticker in ’is ’and.
1908		Magnet 13 June 12: Squaring up to the new boy.
1914		S. Lewis Our Mr Wrenn (1936) 62: Bill Wrenn squared at the rowdy.
1922		S. Lewis Babbitt (1974) 150: Squaring up [...] to platters large of French Fried spuds.
1934		Wodehouse Right Ho, Jeeves 118: It must be a primed, confident Fink-Nottle who squared up to the Bassett for Round No. 2.
1939		P. Gallagher My Story 60: He immediately squared for me although he had not a soul with him, and I had seven or eight lads.
1940		O. Strange Sudden Takes the Trail 31: If it’s a matter o’ squarin’ up with that Sudden gent, I’ll come in cheap.
1944		J. Cary Horse’s Mouth (1948) 7: She squared at me as if she meant to give me a knock.
1958		E. Dundy Dud Avocado (1960) 116: How was I going to square up to all this, I wondered.
1964		R. Abrahams Deep Down In The Jungle 71: The lion jumped back and squared for a fight.
1987		(con. 1930s) L. Redmond Emerald Square 137: ‘Right then ... here’s fight!’ I squared up and O’Connell, grinning, moved in.
1992		P. McCabe Butcher Boy (1993) 39: Tinny voice the mayor squared up to the alien leader and told him he’d never get away with it.
2000		A. Brink Rights of Desire (2001) 134: That was when she squared up to me, arms on her formidable hips.
2008		M. Hanif Case of Exploding Mangoes (2009) 289: The risk ratio might be that of an ant and an elephant squaring up to each other.