Wordorigins.org

Harlot is a borrowing from Old French into Middle English. It did not originally mean a woman of low morals, but rather a vagabond, villain, or otherwise low-life man. From Ancren Riwle, a Middle English tract written sometime before 1225:

And beggen ase on harlot, ȝif hit neod is, his liueneð.
(And beg as does a harlot, give him his needs, his livelihood.)

About a century later, it was being used to refer to a jester or a buffoon, a humorous enterainer. From Richard Rolle of Hampole’s Psalter, written sometime before 1340:

Hoppynge & daunnceynge of tumblers and herlotis, and other spectakils.
(Hopping & dancing of tumblers and harlots, and other spectacles.)