Green’s Dictionary of Slang

bastardly adj.

a negative intensifier.

1915		R. Service ‘The Booby-Trap’ in Ballads of a Bohemian (1978) 572: A booby-trap! Ought to ’a known it! If that’s not a bastardly trick!
1927		(con. 1914–18) L. Nason Three Lights from a Match 238: Them bastardly artillery men went an’ killed a couple o’ Jerries.
1943		W. Guthrie Bound for Glory (1969) 12: This is th’ roughest bastardly boxcar that I ever swung into.
1953		R. Chandler Long Good-Bye 157: But if I may quote the scintillating words of the good Dr Loring, a bastardly bastard with a little black bag, stay away from my wife, Marlowe.
1958		E. Hemingway letter 31 Jan. in Baker Sel. Letters (1981) 881: We are back in the bastardly income tax epoch.
1972		(con. 1930s–40s) N. Conway Bloods 96: That’s my foot not the bastardly blister!
1980		W.C. Anderson Bat-21 104: Some barstardly F-4 pilot had put some eggs in too close and blown up his cornfield.
1989		K. Dunn Geek Love 220: I thought I told you to get rid of that bastardly mold.
2001		S. King Dreamcatcher 98: ‘Wait,’ he said. ‘Bastardly knee’s tryin to lock up on me again.’.

SE in slang uses

In compounds

bastardly gullion (n.) [SE bastardly + Lancashire dial. gullion, a mean worthless wretch]

a bastard’s bastard.

c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions .
1788, 1796		Grose Classical Dict. of the Vulgar Tongue (2nd edn, 3rd edn).
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.