Green’s Dictionary of Slang

a wandering beggar, adopting tattered clothing and posing as a madman.

c.1561		Awdeley Fraternitye of Vacabondes in Viles & Furnivall (1907) 3: An Abraham man is he that walketh bare armed, and bare legged, and fayneth hym selfe mad, and caryeth a packe of wool, or a stycke with baken on it, or such lyke toy, and nameth himselfe poore Tom.
c.1566		Harman Caveat for Common Cursetours in Viles & Furnivall (1907) 47: These Abrahom [sic] men, be those that fayne themselues to haue been mad, and haue beene kept eyther in Bethlehem or in some other pryson a good time, and not one amongst twenty that euer came in pryson for any such cause.
1592		Groundworke of Conny-catching [as cit. c.1566].
1608		Dekker Belman of London D2: Of all the mad rascalls (that are of this wing) the Abraham-man is the moft phantastick: The fellow (quoth this old Lady of the Lake vnto me) that sat halfe naked (at table to day) from the girdle vpward, is the best Abraham-man that ever came to my house & the notablest villaine: he sweares he hath bin in Bedlam, and will talke frantickly of purpose; you see pinnes stuck in sundry places of his naked flesh, especially in his armes, which paine hee gladly puts himselfe to (beeing indeede no torment at all, his skin is either so dead, with some fowle disease, or so hardened with weather) onely to make you beleeue he is out of his wits: he calls himselfe by the name of Poore Tom, and comming neere any body, cryes out, Poore Tom is cold.
1621		R. Burton Anatomy of Melancholy (1850) 216: We have dummerers, Abraham men, &c. And that which is the extent of misery, it enforceth them, through anguish and wearisomeness of their lives, to make away themselves; they had rather be hanged, drowned, &c., than to live without means.
1669		W. Winstanley New Help To Discourse 133: Abraham man, are those we call Tom a Bedlams, terrible enemies to Poultery-ware, shifting his Wenches oftner than most people shift their linnen.
1707		J. Shirley Triumph of Wit 182: The Abram-cove, or Abraham-man is one that dreses himself ridiculously, and pretends at sundry times to be Mad, and in Fits, when indeed he does it to draw People about him, to procure the Advantage of the rest, either in telling Fortunes, or giving them the Opportunity of picking the Pockets of the Gazers.
1754		Scoundrel’s Dict. 18: A poor Man – Abraham-cove.
1822		R. Nares Gloss. (1888) I 3: abraham-men, or tom of bedlam’s men, or bedlam beggars, A set of vagabonds, who wandered about the country, soon after the dissolution of the religious houses; the provision for the poor in those places being cut off, and no other substituted.
1859		Matsell Vocabulum 1: abraham cove A naked or poor man; a beggar in rags.
1867		W.H. Smyth Sailor’s Word-Bk (1991) 14: Abraham-Men. A cant term for vagabonds who formerly begged under pretence of having been discharged destitute from ships.
1882		Breckenridge News (Cloveport, KY) 23 Aug. 3/3: I’m a ‘Abraham-cove,’ p[lease yer honor. [...] A Abraham-cove, a ‘addle-cove,’ and a ‘hickjop’.
1882		Sydney Sl. Dict. (2 edn) 1: Abraham (Sham) - To feign sickness or distress. From ‘Abraham Man,’ the ancient cant term for a begging impostor, or one who pretended to have been mad.
1895		C. Crowe Aus. Sl. Dict [as 1859].
1929		Advertiser (Adelaide) 25 Oct. 32/7: Birmingham tramps and beggars now have their own newspaper. Its title is the ‘Abraham-man’s News.’ ‘Abraham-man’ is the slang term for vagabond.
1932		F. Jennings Tramping with Tramps 212: Abraham Man – a veteran vagrant.