Green’s Dictionary of Slang

(US) a mild expletive; euph. for by Jesus!

1862		J.R. Lowell Biglow Papers 2nd series (1880) 99: By ginger, ef I’d ha’ known half I know now.
1891		M.D. Landon Eli Perkins: Thirty Years of Wit 285: By ginger, he looked mighty pale!
1895		S. Crane Red Badge of Courage (1964) 88: By ginger, it hurt like thunder.
1908		‘Old Sleuth’ Dock Rats of N.Y. (2006) 18: By ginger, she mislaid her letter, and my nephew, a rattling little chap, ‘nipped’ it and gave it to the Cap.
1916		E. Porter David 309: ‘Well, by ginger!’ exclaimed the man again [DA].
1929		‘Ellery Queen’ Roman Hat Mystery 243: Well, by ginger, if you know now, let’s get a move on.
1938		N. Lindsay Age Of Consent 68: By ginger, I’ve had a hell of a time.

(US) an excl. used to mock someone who is seen as behaving in a socially unacceptable way.

1876		J. Miller First Fam’lies in the Sierras 9: ‘Ginger blue!’ cried the Parson.
1909		J. Ware Passing Eng. of the Victorian Era 141/2: Ginger blue (Amer.-Eng., 1856). Exclamation protesting against caddishness.
1910		‘Doss Chiderdoss’ ‘Unseemly Hilarity’ Sporting Times 22 Oct. 1/3: Anon [she] appeared in public in the fearsome garment girt, / Shouts of ‘Ginger! You are barmy!’ from street urchins rude and pert / Caused unthinking men to cachinnate.
1922		‘Gooseberry Wine’ in T.W. Talley Negro Folk Rhymes 41: Don’t never tu’n yo’ back, Suh, / On day good ole gooseberry wine! / Oh walk chalk, Ginger Blue! Git over double trouble.