Green’s Dictionary of Slang

bronstrops n.

also brainstrap
[SE bawdstrot, a pander or procuress]

a procuress.

[UK]Middleton & Rowley A Fair Quarrel IV i: I say thy sister is a bronstrops. [Ibid.] IV iv: Mayst thou first serve out thy time as a tweak, and then become a bronstrops.
[UK]Webster Cure for a Cuckold IV i: A Tweak, or Bronstrops – I learnt that name in a Play.
Brothers of the Blade 5: Pox on’t, the cause of my lying in there so long, was long [sic] of the pocky whore Petronella Burnyard, that insatiate sister of our scabard: This bold Bronstrops would have father’d her bastard upon me.
[UK]R. Brathwait Honest Ghost 96: Their pretence is to Slice this Brain-strap into Sippets.