Green’s Dictionary of Slang

a prostitute, a ‘fallen woman’; citations suggest a street girl rather than a brothel worker or call girl.

[1797		M. Leeson Memoirs (1995) I 69: They ran drunk through the streets [...] broke open the habitations of unfortunate girls].
1825		Pierce Egan’s Life in London 16 Jan. 406/2: The prisoners are by profession ‘unfortunate girls’—that is to say, girls who have the misfortune to prefer street-walking to honest industry.
1827		T. Hood Bridge of Sighs n.p.: One more unfortunate, Weary of breath, Rashly importunate, Gone to her death .
1830		Egan Finish to the Adventures of Tom and Jerry (1889) 75: I had the resolution to steer clear of the ‘Fields of Temptation’; [...] although I do not like to turn my back upon ‘the Unfortunates.’.
1846		Bell’s Life in Sydney 31 Oct. 3/1: An UNFORTUNATE.—Anne Fry, an interesting looking young female, deeply pitted by the smallpox, mode her thirty-first appearance before Capt. Innis, on Monday.
1857		J.E. Ritchie Night Side of London 70: Here, as elsewhere, we see a few of the class of unfortunates, whose staring eyes would fain extort an admiration which their persons do not justify.
1858		‘Shadow’ Midnight Scenes 33: Hurrying along ‘one more unfortunate’ is met; hunger and vice have committed ravages upon her pale haggard countenance.
1867		J. Greenwood Unsentimental Journeys 37: Three unfortunates, two of which are old customers and sisters, for coffee and cake.
1867		Nat. Police Gaz. (NY) 21 Dec. 2/5: Another Unfortunate Another of that unfortunate class against which soiety has pronounced her decree [...] threw off her burden and with it her life.
1877		W.H. Mallock New Republic III ii n.p.: Hoping I might see some unfortunate cast herself from the Bridge of Sighs [F&H].
1895		Crowe Aus. Sl. Dict. 91: Unfortunate, a general name for a street woman.
1896		E. Pugh Man of Straw 347: Her name was Alice Shallers, ma’am. She was an – er – unfortunate, ma’am.
1925		N. Lucas Autobiog. of a Thief 152: There were girls present who were obviously well-bred, there were actresses, and unfortunates.
1935		R.T. Hopkins Life and Death at the Old Bailey 231: She is an ‘unfortunate,’ about nineteen years of age.
1973		R. Todasco Intelligent Woman’s Guide to Dirty Words.
1994		(con. 1920s) K.C. Kearns Dublin Tenement Life 55: I don’t feel any shame coming from the Monto, but the reputation was there cause of the girls, In them years they was called ‘unfortunate girls.’ [Ibid.] 69: They were called ‘unfortunates’ ... ‘unfortunate girls.’.
2015		L. McInerney Glorious Heresies 90: ‘Oh, she’s one of the unfortunates. She’s on the streets [...] she’s usually down the quay’.