Green’s Dictionary of Slang

holer n.

also hole-monger
[hole n.1 (1b) + SE sfx -monger; note 13C–15C SE holour, a fornicator or whoremonger and, as such, applied to men only]

1. [16C+] a womanizer, a successful seducer.

2. [19C] a male prostitute.

3. [19C] a pimp.

4. [late 19C] a prostitute.