Adult pilled means: To be adult pilled is to have been so thoroughly confronted by the realities of grown-up life that you've been fundamentally changed by them - often in a bittersweet, slightly defeated way. Maybe. 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.