"yampy check" means: A real-time evaluation of whether someone is acting completely daft, scatty, or willfully ridiculous. The yampy check is issued when a perso.... 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.