Green’s Dictionary of Slang

1. a tramp, spec. one of the Forty-second Order of Vagabonds [SE cursitor, a courier].

1688		R. Holme Academy of Armory Ch. iii item 68b: Give me leave to give you the names (as in their Canting Language they call themselves) of all (or most of such) as follow the Vagabond Trade, according to their Regiments or Divisions, as 1. Cursitors or Vagabonds.
c.1698		B.E. Dict. Canting Crew n.p.: Cursitors, c. Vagabonds; the first (old) Rank of Canters.
1725		New Canting Dict. n.p.: cursitors the Forty-second Order of Vagabonds; anciently the First Rank of Canters, who pretend to be a sort of itinerant Office-men, or reduced Lawyers, and assuming to themselves some Knowledge of the Quirks and Quiddities of the Law, were perpetually fomenting litigious Brawls, and insignificant Contentions, among the Scum of the Vulgar, and especially among clamorous, vindictive Women, whom they never left, if they once obtained their Ear, till they had reduc’d them to Beggary and the Ducking-Stool.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict.

2. one of the ‘broken, pettifogging attornies or Newgate solicitors’ (Grose, 1785) [ult. SE: ‘one of twenty-four officers or clerks of the Court of Chancery, whose office it was to make out all original writs de cursu, i.e. of common official course or routine, each for the particular shire or shires for which he was appointed’ (OED)].

1725		New Canting Dict.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Cursitors, broken, pettifogging attornies or Newgate solicitors.
1809		G. Andrewes Dict. Sl. and Cant n.p.: Cursitors broken-down lawyers, Newgate attornies .
1811		Lex. Balatronicum.
1821		Flash Dict.
1835		G. Kent Modern Flash Dict. 11: Cursitons [sic] – broken down lawyers, Newgate attorneys.
1848		Flash Dict. in Sinks of London Laid Open.
c.1850		Duncombe New and Improved Flash Dict.
1859		Matsell Vocabulum 23: curtisons [sic] Broken-down lawyers; Tombs skinners.