Green’s Dictionary of Slang

1. a high-class prostitute; orig. a woman hired to ride in Hyde Park.

[1861		Fun 28 Sept. 16: [cartoon caption, of burglar sidesaddle on a donkey] The Pretty Housebreaker!].
1861		broadside ballad The pretty little horse-breakers / Are breaking hearts like fun.
1862		G.A. Sala in Temple Bar mag. 54: It is considered the thing just now to run down dashing horse-women by fastening upon them the epithet ‘pretty horse-breaker’.
1865		R.S. Surtees Facey Romford’s Hounds 77: What! they were to have pretty horse-breakers down in the country, were they?
1865		Public Opinion 30 Sept. n.p.: These demi-monde people, anonymas, horse-breakers, hetairae... are by degrees pushing their way into society [F&H].
1870		W.B. Jerrold Cent per Cent 115: And these green and ‘fast’ noblemen, the height of whose ambition was to back a winner for the Derby, or win the pretty horse-breaker who was for the moment in vogue.
1880		New Babylon 5/2: The pretty horsebreaker, the horsedealer and his foreman adjourned for refreshment, and to complete the deal.
1890–1904		Farmer & Henley Sl. and Its Analogues.
1895		C. Crowe Aus. Sl. Dict. 61: Pretty Horse Breakers, expressive of hearts broken by the demi-monde.
1902		M. Cholmondeley Moth and Rust, and Other Stories 10: ‘I don’t know what I’ve done,’ said Mrs. Trefusis, ‘that my only son should marry a pretty horse-breaker.’.
1913		H. Maxwell Life and Letters of [the] Fourth Earl of Clarendon 226: A beautiful horsewoman, original of the type ‘pretty horse-breaker’.

2. attrib. use of sense 1.

1879

E. Holmes Amabel Vaughan, and Other Tales 99: Miss Jarvis, a blonde young lady of fast manners, loud voice, and a good deal in the pretty horse-breaker style.