Green’s Dictionary of Slang

a small boy used by robbers to enter a house through a window that would be too small to allow a man to climb through it.

1608		Dekker Belman of London G: The Diuer workes his Iugling feates by the help of a boy, (called a Figger) whom hee thrusts in at a casement [...] this Figger deliuers to the Diuer what snappings he findes in the shop or chamber.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Fagger, a little boy put in at a window to rob the house. [Ibid.] Figger. A little boy put in at a window to hand out goods to the diver.
1809		G. Andrewes Dict. Sl. and Cant n.p.: Figure a little boy put in at the window to hand the goods out to his accomplices in the street.
1811		Lex. Balatronicum [as cit. 1785].
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1835		G. Kent Modern Flash Dict. 13: Figure – a little boy put in at a window, to hand goods to his accomplices.
1848		Flash Dict. in Sinks of London Laid Open [as cit. 1835].
c.1850		Duncombe New and Improved Flash Dict. [as cit. 1809].
1859		Matsell Vocabulum 30: fagger A small boy put into a window to rob the house, or to open it for others to rob. [Ibid.] 31: figger A juvenile thief put through side-lights at outside doors to unbolt the door and admit other thieves to the house.
1895		Crowe Aus. Sl. Dict. 27: Fagger, a small boy put through a window to steal.
1901		Argus (Melbourne) 20 Sept. 6/4: Amongst these small fry of the profession [are] the fagger, or small boy who is put through a window; the gilt dubber, or hotel thief; the Lily prigger, snow dropper or robber of clothes lines , who gets away with a roll of snow or milky duds.