Green’s Dictionary of Slang

strum n.2

[abbr. SE strumpet]

a sexually available (young) woman; a prostitute.

[UK]B.E. Dict. Canting Crew n.p.: Strum [...] a handsom Wench or Strumpet.
[UK]W. King York Spy 43: Scarce one appeared above the Degree of an Alderman’s Pimp, nor one Strum, that cou’d demand above Two pence Wet and Two pence Dry, for a Nights Occupation.
[UK]N. Ward Amorous Bugbears 28: As if her wealthy Keeper had borrow’d his Wife’s Girdle, out of her Casket of Jewels, to adorn his Mistress for the Day, that the proud Curtesan might appear the less like a Strum.
[UK]Bailey Universal Etym. Eng. Dict. [as cit. c.1698].
[UK]‘Bill Stroke’Em’ in Gentleman’s Private Songster in Spedding & Watt (eds) Bawdy Songbooks (2011) III 380: One night he met a pretty lass, / He wanted much a strum.
[UK]‘Walter’ My Secret Life (1966) V 1035: He thinks from a large acquaintance with these useful strums, that their cousins and friends [...] get the virginities for nothing, and before the girls are fifteen years old.
[US]E. Wittmann ‘Clipped Words’ in DN IV:ii 121: strum, from strumpet.