Main character means: Someone behaving as if the world revolves around them - sometimes self-applied in an empowering register, sometimes critically ("main character syndrome"). 2020s self-mythologising vocabulary.. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.