"sheriff-substitute" means: The acting sheriff in a Scottish county or city, like the sheriff-depute appointed by the Crown, but unlike the sheriff-depute forced to res.... 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.