Green’s Dictionary of Slang

a form of Lord! and similarly used in mild oaths.

1704		Cibber Careless Husband IV i: O Lud! I swear I don’t like it.
1722		S. Centlivre Artifice Act II: Oh Lud! what would you have me do?
1751		Smollett Peregrine Pickle (1964) 227: O lud! O lud! (exclaimed the painter, with a loud laugh).
1762		Foote Orators in Works (1799) I 193: O Lud! it is unknown what knowledge we got.
1775		Sheridan Rivals (1776) I ii: Lud! ma’am, here is Miss Melville.
1794		Sporting Mag. May IV 124/1: Lud, Sir, I’ve been every where.
1816		W.T. Moncrieff All at Coventry I ii: Lud, I wish he would come!
c.1822		‘The Dandy’ in Holloway & Black II (1979) 274: How stilish! lud how handsome, how handy O.
1833		John Neal Down-Easters II 33: Lud! how grave you are!
1884		M.V. Fuller Mrs Rasher’s Curtain Lectures 25: O Lud, Rasher, Fitz Simmons and I have had such a day!
1947		N. Marsh Final Curtain (1958) 30: ‘Oh, lud!’ Cedric complained.