Green’s Dictionary of Slang

one who lends money to losing gamblers, taking advantage of their desperate need for new funds to extort the highest possible interest.

c.1698		B.E. Dict. Canting Crew n.p.: Impost-taker c. one that stands by and Lends Money to the Gamester at a very high Interest or Premium.
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.
1811		Lex. Balatronicum.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1859		Matsell Vocabulum 44: impost-taker One who lends money to thieves and gamblers at very high rates.