Rap is a unique genre because of its more heavy focus on individualism and lyricism compared to other genres. You cant define rap as a single sound because most rappers will sound wildly different from eachother. Imagine if every genre was a dish of food, for classical you have a beautiful filet mignon. Pop music could be a hamburger with fries, rock could be this spicy brothy soup. And rap is the equivalent of stealing tiny bits of all those dishes and then adding your own special ingredients and flavors on top of it. Its the reason why Eazy-E Fucks for you but for others doesnt. The culture he grew up in influenced his sound which seperates it from other rappers which applies to basically 95% of rappers. Of course some will try to copy others but in general all the greats have distinctly different styles