Green’s Dictionary of Slang

break a leg v.

1. (also break one’s leg) of a womanizing man, to become father to a child, whether one wishes to or not.

[UK]W. Carr Dial. of Craven [Yorks.] 285: He hath broken his leg, ‘of a dissolute person on whom a child has been filiated’.

2. (also break one’s leg) to become pregnant out of wedlock; often ext. as break a/one’s leg above the knee.

[UK]Beaumont & Fletcher Wild-Goose-Chase IV i: She was first a Ladies Chamber-maid, there slip’d And broke her leg above the knee.
[UK]Head Art of Wheedling 189: Though she hath broken her leg, she is sound enough for a Drawer, newly out of his time, who, having credit for wine, his house is furnished with the money that did set his wife’s broken leg.
[UK]J. Ray Proverbs (3rd edn) 200: She hath broken her leg above the knee. i.e. had a bastard.
[UK]Grose Classical Dict. of the Vulgar Tongue n.p.: leg [...] to break a leg, a woman who has had a bastard, is said to have broken a leg.
[UK]Lex. Balatronicum [as cit. 1785].
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue [as cit. 1785].
[US]L.W. Payne Jr ‘Word-List From East Alabama’ in DN III:iv 294: break one’s leg, v. phr. Of a woman, to become with child illegitimately.
[US]E. Field ‘A French Crisis’ in Facetiae Americana 19: She’d break her leg above the knee, pound, click and tread as well.
[US] in DARE.
[US]H. Rawson Dict. of Invective (1991) 309: Variations on this theme, all casting the event in terms of an accident, include [...] break a leg, and break a leg above the knee.

3. (also break one’s knee) of a young woman, to lose one’s virginity, to be seduced.

[UK]Farmer Vocabula Amatoria (1966) 134: forligner. To copulate; ‘to break one’s knee’.
[US]Monteleone Criminal Sl. (rev. edn) 33: break a leg To be seduced; to make a woman pregnant.

4. to seduce.

[US]Matsell Vocabulum.
[US]Trumble Sl. Dict. (1890).

5. (US) to be arrested.

[US]J.M. Sullivan Criminal Sl. 4: Broke a leg – Got arrested.
[US]NY Tribune 8 June 7/5: To announce he is under arrest, he says he has ‘broken a leg’.
[US]G. Henderson Keys to Crookdom 400: Capture. Caught [...] broke a leg.

6. (orig. US) to hurry.

[US] N.Y. Eve Journal 5 Aug. 15: Tear up to 1492 Columbus and slip this wire to Mr. P.J. Flanigan – and break a leg getting back [HDAS].
[US]Berrey & Van Den Bark Amer. Thes. Sl.
[US]J.D. Salinger Catcher in the Rye (1958) 63: I could picture her breaking a goddam leg to get to the phone and tell my mother I was in New York.