Afk mode means: AFK mode is the state of being mentally or physically checked out - not just away from a screen, but fully off the grid by choice. Entering AFK mode means you're done with obligations,. 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.