What does it mean to be Christian?

Does it mean that one confesses “sin?”
Does it mean that one acts like a good person and treats others with love?
Does it mean that a person resembles a cultural idea of what others think is Christian?
Is a Christian someone who is committed to serving in the church?
Is someone Christian if they are trying to be a follower of Jesus?
Does it mean that a person will have a hopeful afterlife?
Does it mean that one is reconciled to Yahweh through some exterior means?