Green’s Dictionary of Slang

(Aus./UK Und.) a young woman, esp. a prostitute.

c.1698		B.E. Dict. Canting Crew n.p.: Giglers, c. wanton Women.
1725		New Canting Dict. [as cit. c.1698].
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Gigglers; wanton women.
1811		Lex. Balatronicum [as cit. 1785].
1838		Crim.-Con. Gaz. 6 Oct. 49/1: The rout of a Countess, where she’s exhibited as a broad-but to the gigglers.
1854		Thackeray Newcomes I 239: Show me a gracious virgin bearing a lily: not a leering giggler.
1890		Dead Bird (Sydney) 11 Oct. 5/2: She [...] openly informed us in the presence of four or five big policemen that she and the gigglers who were with her were going to make things hum.