Ribald is an adjective you would use to describe someone who makes dirty sexual jokes. Vulgar, perverted, but still kind of funny — that’s a ribald person.
Remember the time Uncle Marvin told hilarious stories about his sex life? Everyone was rolling with laughter, except your grandmother, who thought Marvin’s ribald tales were disgusting. People are conflicted about whether being ribald is good or bad, and the fact that its root means “indulge in licentious pleasure” and “prostitute” doesn’t clear up the matter much. Should you feel like behaving in a ribald way, remember that your saucy sense of humor might be offensive to others.