Green’s Dictionary of Slang

a prostitute; thus trading pupil n., a newly recruited whore.

1610		Beaumont & Fletcher Scornful Lady II i: There are madams [...] theres tradinge pupill.
1664		C. Cotton Virgil Travestie (1765) Bk IV 72: That she, Now car’d no more for her good Name, / Than any common Trading Dame.
1683		Whores Rhetorick 73: The most convenient habitation for a Trading Lady, is in a small convenient House of her own.
1750		‘Doctor A--- Advice to his Patients’ in Button Hole Garland 5: All the trading Sparks and Dames, / Are subject to Venereal Flames.
1753		Thief-Catcher 35: Very many of those Baliffs, and most, if not all their Followers, Live and Cohabit with lewd Women, Bawdy-house Keepers [...] and such like Trading Ladies.
c.1800		‘Song No. 13’ Papers of Francis Place (1819) n.p.: Near to Temple bar, liv’d two trading women.