They fuck with skill and artistry. The professionals, anyway.

Yes, the technical definition is "a woman who engages in sexual acts for money". However, the word "whore" is an old one. I feel it does not properly accommodate the modern pornstar. They are performers, and fucking is their craft. They aren't really prostitutes, which is who the word was initially applied to. And women of loose sexual morals in general. Are pornstars morally loose? Maybe. But since they are professionals and get paid for their performance it is their job to be morally loose. Which isn't actually morally loose since they are performing.