The Gospel Coalition has a great article by Tim Keller on idolatry in a postmodern age. In the article Keller discusses why defining sin as the breaking of God’s law is not the best approach in a postmodern world that rejects absolute truth. He says that presenting sin as an act of idolatry can better communicate what sin is and what sin does. I would highly recommend the article to you.
Talking About Idolatry in a Postmodern Age – The Gospel Coalition