"NNR" means: (used in forums dedicated to nappies (diapers) to signify that the succeeding post is not related to nappies; i.e. it is off-topic).. 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.