Sex maniac is a derogatory term used to describe someone who has an obsessive and excessive interest in sexual activities. Although the term is often used colloquially, it implies a negative connotation and can be offensive to some people. There are several synonyms that can be used to describe a sex maniac, such as nymphomaniac, hypersexual, sex addict, sex fiend, and the more clinical term, hypersexual disorder. It's important to remember that these terms should be used with sensitivity and only to describe someone's behavior, rather than as a label that defines their entire personality or identity.