Academentia mode means: The state of being fully lost in academic overthinking - when someone shifts into a register so theoretical, formal, or citation-heavy that they become useless in a normal conversation. Often used. 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.