"yaar core" means: The aesthetic and lifestyle built entirely around the warmth, loyalty, and intimacy of close friendship — late-night voice notes, matching p.... This is a fairly neutral word with no inherent risk attached. There is no real cause for parental concern; it is descriptive vocabulary rather than something dangerous. If your child uses it, context will usually make the meaning clear. A brief, curious question about where they heard it is generally enough to know whether to follow up.