Green’s Dictionary of Slang

a mild oath, lit. ‘God’s wounds’.

[1535		R. Copland Hye Way to the Spyttel House line 360: There they reuell as vnthryfty braggers, With horyble othes swerynge as they were wood, Armes, nayles, woundes [...] With all other wordes of blasphemy].
1594		Merry Knack to Know a Knave F2: Zwouns, they are both agreed to cuckold me.
1598		Jonson Every Man In his Humour III v: Cuckold? ’Swounds, cuckold?
1599		H. Porter Two Angry Women of Abington D4: Hostesse, swounes you whore, Harry Hooke’s a rascall.
1605		Chapman & Jonson Eastward Ho! III ii: ’Swounds, yet again!
1612		N. Field Woman is a Weathercock I ii: ’Swounds, I’ll be revenged upon ye all!
1712		J. Arbuthnot Hist. of John Bull 83: That ever thou should’st be dazzled with the [...] mountains of gold, that old Lewis promises thee! ’dswounds.
1738		Swift Polite Conversation 76: Swolks, I must be going, by’r Lady.
1822		(con. early 17C) W. Scott Fortunes of Nigel I 279: Uh, gad! – Swouns, I shall never survive the idea!
1902		(con. 18C) Pittsburg Press (PA) 16 May 6/6: ‘Swounds, Mr Attorney, I am in your debt’.