Green’s Dictionary of Slang

(UK Und.) the dupe or victim of a confidence trickster or a prostitute.

1591		Greene Notable Discovery of Coosnage in Grosart (1881–3) X 39: The haue sundry praies that the cal simplers, which are men fondly and wantonly geuen, whom for a penalty of their lust, they fleece of al that euer they haue.
1608		Dekker Belman of London H1: The whore is then called the Traffick. The man that is brought in is the Simpler. The Ruffian that takes him napping is the Crosbiter.
1610		Rowlands Martin Mark-all 12: These and many more might you haue busied your braine about, and not thus scandalously and satirically to tyrannize ouer vs as your Crossbiter do ouer their Simplers.