Academy szn means: The period at the start of an academic year, sports preseason, or a new training cohort when everyone is fresh, motivated, and grinding through structured learning before the real competition or work. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. It is sporting vocabulary and harmless in itself. 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.