Green’s Dictionary of Slang

abram n.

[abbr. abram-man n.]

1. (UK Und.) a wandering beggar, adopting tattered clothing and posing as a madman.

[UK]Rowlands Martin Mark-all 37: He maunds Abram, he begs as a madde man.
[UK]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.
[UK] ‘Canting Words and Terms’ in Bailey Universal Etym. Eng. Dict.
[UK]B.M. Carew ‘The Oath of the Canting Crew’ in Farmer Musa Pedestris (1896) 50: No strange Abram, ruffler crack, / Hooker of another pack.
[UK]Grose Classical Dict. of the Vulgar Tongue n.p.: [as cit. 1674].
[UK]B.M. Carew Life and Adventures.
[UK]Egan Grose’s Classical Dict. of the Vulgar Tongue.

2. a gullible fool, a cuckold.

[UK]J. Taylor Juniper Lecture 93: Shee makes her husband a very Asse, an Abram, and a Ninnihammer [...] though shee be counted a Whoore or a light woman.

3. a counterfeiter.

[UK]Mercurius Democritus 10-26 Aug. 98: A Jewish Abram [...] casting or graving spelter [i.e. solder] seals for cheating Brokers.

In compounds

abram suit (n.) (also abraham suit) [SE suit, a petition]

working as a writer of begging letters, the pursuit of many small-time 19C confidence tricksters.

[UK]Kendal Mercury 17 Apr. 6/1: A cove has to do many things for his scran [...] and the Abraham Soot’s (begging letter imposture) no go.
[UK]Barrère & Leland Dict. of Sl., Jargon and Cant.

In phrases

sham abram

see separate entries.