The word harlot is a slightly archaic term for "immoral woman" and is often a euphemistc term for "prostitute". However, it didn't always carry that meaning. When harlot entered English around the 1200s CE, it described an "unscrupulous man", occasionally just a "man" in general! The former definition was more used, albeit, and this resulted in the word being extended to cover all kinds of immoral people, and from that just women. The modern definition was cemented when Bible translations in the 1500s used harlot as a translation for "prostitute". Anyway, the word itself came to us from a French word for "male tramp", which took various forms, including harlot, arlot, and herlot. Now, the origin for this is uncertain, but some philologists theorize that it is rooted in the Proto-Germanic harjaz, which meant "army" but also "soldier" (possibly how the "male" definition came about) and would be from PIE ker, also "army". A French word from Proto-Germanic is less common than from Latin, but still frequent because of the muddles of the Franks and all.
Adam Aleksic, an incoming freshman at Harvard University, has been described as the internet's sixth most famous etymologist. He has disturbing interests in linguistics, vexillology, geography, board games, limericks, and law, and he loves writing about himself in the third person.
The Etymology Nerd