Green’s Dictionary of Slang

1. a general intensifier, lit. ‘most damnable’; thus superlative god-damn(e)dest.

1620		in E. Cray Erotic Muse (1992) 2: The old wife got up for to take a long shit. / The God damned old sea crab grabbed her by the slit.
1852		Edgefield Advertiser (SC) 13 Oct. 2/2: You see that God damned thing there?
1862		in T.P. Lowry Stories the Soldiers Wouldn’t Tell (1994) 41: If you arrest me, I will rip your God damned guts out and scatter them over the parade ground.
1863		Dublin Eve. Mail 4 May 4/3: It is none of your God damned business.
1874		‘A.P.’ [Arthur Pember] Mysteries and Miseries 136: ‘Hat Spoor was God-damned fool enough to go and do as I told him!’ .
1880		Butler Citizen (PA) 17 Mar. 1/4: He replied, ‘You’re a G-D- liar’.
1916		Sun (NY) 29 Nov. 14/2: What the mate axed the captain [...] was a little see-vility, and that of the commonest goddamned kind.
1918		H.V. O’Brien diary 15 Feb. Wine, Women and War (1926) 29: If and when I do get home, I’ll be the same God damned crab I was when I went away.
1927		(con. 1914–18) L. Nason Three Lights from a Match 140: I’ll give you the God-damnedest kick on the bottom that you ever got in your life!
1929		E. Booth Stealing Through Life in Hamilton Men of the Und. 260: You’re just a God-damned liar.
c.1930		(ref. to late 19C) N. Kimball Amer. Madam (1981) 108: The goddamnedest big roses growing all over everything.
1937		E. Anderson Thieves Like Us (1999) 7: ‘Like goddamned hoboes,’ T-Dub said.
1940		R. Chandler Farewell, My Lovely (1949) 12: Kind of take your goddamned mitt off my shirt.
1940		in W.C. Fields By Himself (1974) 371: This is the God-damndest excuse I have ever heard for cutting a gag out of a picture.
1951		M. Spillane One Lonely Night 76: Those goddamned bastards!
1960		C. Cooper Jr Scene (1996) 83: I was talking on the goddamned phone!
1965		C.D. Bryan P.S. Wilkinson 57: This is the foulest, goddamdest country I’ve ever seen!
1977		A. Clarke Prime Minister (1978) 163: This is the next fucking government, take it from me, Your-humble-god-damned-servant.
1981		J. Ellroy Brown’s Requiem 17: It’s those goddamned Ricardo Montalban Cordoba ads.
1999		E. Bunker Mr Blue 58: Goddamned rats had come up through the shithole.

2. a positive term of admiration; usu. as god-damnedest.

1945		E. Wilson I Am Gazing Into My 8-Ball 26: I will bet there is no other such hostess in the world, for she is the gahdamnnedest woman I ever saw .
1952		Lait & Mortimer USA Confidential 202: It is the biggest, the fastest-growing and the richest spot in the whole god-damned state of Texas, which is the god-damnedest state in the world.
1981		G.V. Higgins Rat on Fire (1982) 140: That Tackles [...] That guy is the goddamnedest guy I ever met. And he is smart, too.