The more holy someone or something is, the more separate he or it is from things that are common or normal. The opposite of holiness is not sinfulness. It is commonness – or, to use the old word, profaneness. When God says He is holy, He means that He is different from us. He means that He constantly and actively separates Himself from all sin, wickedness, evil, and moral corruption – that is, all that is common to this world.