Whore

1530s spelling alteration (see wh-) of Middle English hore, from Old English hore "prostitute, harlot," from Proto-Germanic *horaz (fem. *horon-) "one who desires" (source also of Old Norse hora "adulteress," Danish hore, Swedish hora, Dutch hoer, Old High German huora "whore;" in Gothic only in the masc. hors "adulterer, fornicator," also as a verb, horinon "commit adultery"), from PIE root *ka- "to like, desire," which in other languages has produced words for "lover; friend."
Whore itself is perhaps a Germanic euphemism for a word that has not survived.