Green’s Dictionary of Slang

a general excl. of exasperation.

1831		Satirist (London) 31 July 135/1: ‘G—d d—n it,’ said Elliston.
1834		Dublin Eve. Packet 24 Nov. 3/3: God damn it [...] that tour [...] was chiefly the cause of this cursed event.
1836		Marryat Mr Midshipman Easy II 305: ‘I hope I have not sworn — I hope not.’ ‘Not a word,’ said Jack – ‘I was close to you all the time — you only said, “God preserve us!”’ ‘Only that? I was afraid that I said “God d--n it!”’.
1849		W. Kent Guardian 6 Jan. 6/3: Brien started up and said, ‘God damn it, where is your money’.
1865		Derry Jrnl 25 Mar. 2/6: God damn it, Sir, it’s all stuff and nonsense.
1888		Nat. Trib. (Wash., DC) 6 Sept. 3/6: Goddammit No!
1904		Watchman & Southron (Sumter, SC) 31 Aug. 3/3: Mr Folk said, God damn it, come in the road.
1918		E. Pound letter 7 June in Read Letters to James Joyce (1968) 143: Gawd damn it, it is Writing, with a large W. and no C.
1929		D. Parker ‘Big Blonde’ Penguin Dorothy Parker (1982) 195: God damn it, I’m through, I’m telling you.
1932		Falkirk Herald 31 Dec. 7/2: As soon as he opens his mouth to say ‘Goddammit’.
1939		H. Miller Tropic of Capricorn (1964) 250: God-damn it, Henry, you’re the only real friend I’ve got.
1939		K. Tennant Foveaux 84: ‘God damn it,’ he would roar. ‘You’ve got nothing to do but sit round all day and dress yourselves. Why isn’t dinner ready?’.
1941		G. Kersh They Die with Their Boots Clean 45: God damn it, any soldier’d be shamed to stand in a rank like a dog’s leg!
1948		N. Mailer Naked and Dead 144: Goddammit [...] can’t you guys keep quiet?
1959		E. De Roo Go, Man, Go! 13: God-dammit-to-hell!
1964		H. Selby Jr Last Exit to Brooklyn 261: This heres for usall to use an ghuddamit Im gonna use this mothafucka if ah gotta break yo fuckin haid.
1970		E. Tidyman Shaft 76: Go, goddamnit!
1978		P. Theroux Picture Palace 31: Goddamit, yes!
1982		G.V. Higgins Patriot Game (1985) 80: Goddammit, it’s a rare day you don’t find out something new in this great land of ours.
1989		M. Amis London Fields 136: I have never screwed around (why not, God damn it?).
1998		D. Hecht Skull Session 270: Eddy, goddamn it, come on!
2000		C. Cook Robbers (2001) 5: Eddie said, Goddammit to hell.