Phonetic spelling of hostler, from late 14thC.
ostler (plural ostlers)
- A person employed at an inn, hostelry, or stable to look after horses; a groom
1979, J.G. Ballard, The Unlimited Dream Company, chapter 21:
Followed by the sun, I left the grounds of the mansion and entered the deserted park, an ostler leading a large and passive work-horse out to the day's labour.
a groom (at inn, hostelry, stable)