Green’s Dictionary of Slang

sempstress n.

also seamster, sempster, semptress

a prostitute.

[UK]Marston Malcontent III iii: [I love] Dogs, Dice and Drabs, ... have beate my Shoomaker, knockt my Sempstress.
[UK]N. Ward Step to the Bath 16: There was Chaucer’s Sempstresses,... London-Jilts with Tails like Countesses, and case-harden’d Impudence.
[UK]N. Ward Secret Hist. of Clubs 164: [A bully] with a lac’d Hat, Beaux like, under his Left Arm, and in his Right Hand a Grays-Inn Semptress tiffl’d up with taudry Laces, old Ribbonds, and black Bugles, as if she was Dress’d to act a Slattern’s Part in some old slovenly Comedy.
[UK] in D’Urfey Pills to Purge Melancholy VI 93: The finest Sempster in this Town May use my Needle at a pinch, And do themselves great Pleasure.
[UK]N. Ward Wandring Spy Pt 2 in Misc. IV 49: An Exchange Seamster [...] That keeps a Shop [...] For Countenance, but sins for Pay.
[US] in G. Legman Limerick (1953) 208: A sempstress at Epping-on-Tyne / Used to peddle her tail down the line.