In the biblical sense, being holy means to be set apart for the purpose of the work of God to be used for His good work. But in order to do that you must first be cleansed( or in other words, saved). So many of us self professed Christians today claim to be set apart, all the while living a life that looks like the rest of our carnal society. Our Lord tells us we are to live in the world, not be a part of the world. (John 17:14,15)