The term "sex-fiend" is considered derogatory and sexist, therefore it is important to use more appropriate and respectful alternatives. Some synonyms that can be used to describe someone who has a high sex drive or an obsession with sex include: sex-positive, hedonistic, libertine, sensualist, eroticist, sex enthusiast, passionate, or sexually adventurous. It is important to remember that each of these terms has its own nuances and connotations, so it is crucial to choose the one that fits the context and tone of the conversation or writing. In any case, using respectful and positive descriptors to talk about someone's sexual preferences and desires is a better approach than using derogatory terms.