Green’s Dictionary of Slang

abbot n.

1. (UK Und.) a prison warden [SE abbey, as generic for prison].

[UK]G. Kent Modern Flash Dict.
[UK]Duncombe New and Improved Flash Dict.

2. a brothel-keeper’s husband or lover [the male counterpart of the abbess n.].

[UK]Farmer & Henley Sl. and Its Analogues.