Green’s Dictionary of Slang

(UK Und.) a criminal pedlar.

c.1566		Harman Caveat for Common Cursetours in Viles & Furnivall (1907) 60: These Swadders and Pedlars be not all euill, but of an indifferent behauiour.
1592		Groundworke of Conny-catching [as cit. c.1566].
1665		Head Eng. Rogue I 38: The rest in order thus [...] Prigges, Swaddlers.
1674		Head Canting Academy (2nd edn) 4: Nor will I suffer him [...] to be abused by any strange Abrams, Rufflers, Hookers, Palliards, Swadlars, Irish Toyls, Swig-men, Whip-Jacks, Jark-men, Bawdy-baskets, Dommerars, Clapperdogeons, Patricoes, or Curtalls.
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 [...] Swadlers.
c.1698		B.E. Dict. Canting Crew n.p.: Swadlers, c. the tenth Order of the Canting Tribe.
1707		J. Shirley Triumph of Wit 186: Not suffering them to be abused by any strange Pallards, Ruffres, Hookers, Swadlers, Irish Toyls, Dummerers, Jarkmen, Whipjacks, Glimmerers, Maunders, or the like, or any other Out-lyers.
1725		New Canting Dict. n.p.: swaddlers the Tenth Order of the Canting Tribe; Rogues, who, not content to rob and plunder, beat and barbarously abuse, and often murder the Passengers.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. 1725].
1749		B.M. Carew ‘The Oath of the Canting Crew’ in Farmer Musa Pedestris (1896) 51: No swigman, swaddler, clapperdudgeon; / Cadge-gIoak, curtal, or curmudgeon.
1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: swadlers. The tenth order of the canting tribe (cant), who not only rob, but beat, and often murder passengers.
1811		Lex. Balatronicum [as cit. 1785].
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.
1848		Flash Dict. in Sinks of London Laid Open.
1859		Matsell Vocabulum 88: Sometimes fellows who pick a quarrel with a man, beat him, and at the same time rob him, are called swaddlers.
1861		(con. 15C) C. Reade Cloister and Hearth (1864) II 33: Come with me to the ‘rotboss’ there, and I’ll show thee all our folk and their lays [...] ‘Rufflers,’ ‘whipjalks,’ [sic] ‘dommerars,’ ‘glymmerars,’ ‘jarkmen,’ ‘patricos,’ ‘swadders,’ ‘autem morts,’ and ‘walking morts’.