Green’s Dictionary of Slang

a man who runs a brothel designed less for providing sex, and more for robbing or blackmailing the clients.

1890–1904

Farmer & Henley Sl. and Its Analogues I 4/2: Abbot, subs. (old). – The husband or ‘fancy man’ of an ABBESS (q.v.) [...] They were occasionally spoken of as croziered abbots, or abbots on the cross, in which case the establishments over which they mounted guard were not so much brothels as panel cribs (q.v.), where prostitution served mainly as a cloak for robbery.