Green’s Dictionary of Slang

abram-sham n.

[sham abram v.]

the practice of travelling the country posing as a madman.

[UK]W.E. Henley ‘Villon’s Good-Night’ in Farmer Musa Pedestris (1896) 174: You bible-sharps that thump on tubs, / You lurkers on the Abram-sham.