"Dr. J" is a popular nickname for Julius Erving, a former American professional basketball player. When referring to him, there are a few different synonyms that can be used, depending on the context. Some people might simply call him "Julius" or "Erving," while others might opt for a more specific nickname like "The Doctor" (in reference to his basketball skills) or "The Dunking Machine" (because of his legendary dunking abilities). In some cases, people might even refer to him as "The King of the ABA" (referring to his time as a star player in the American Basketball Association). Whatever nickname you choose, it's clear that Dr. J is a beloved and iconic figure in the world of basketball.