There are several synonyms available for the word "sado-masochistic," which describes a sexual activity involving both sadism and masochism. The term BDSM is commonly used as a shorthand for this activity, which stands for bondage and discipline, dominance and submission, and sadism and masochism. Other synonyms for sado-masochistic include kink, fetish, and alternative sexuality. Some people describe it as power play or erotic domination, while others may use the terms rough sex or eroticism. It's important to remember that any sexual activity should be consensual and safe for all parties involved, and communication is key to ensuring that everyone's boundaries and desires are respected.