Green’s Dictionary of Slang

Fauntleroy v.

[Henry Fauntleroy, British criminal, hanged for forgery in 1824]

(US) to act as a forger; also as n.

[US]Commercial Advertiser (N.Y.) 25 Jan. 2/6: A young man who has been Fauntleroying, or committing forgery in Chester county. [Ibid.] 29 Jan. 2/3: [headline] Another Fauntleroy case.