"national serviceman" means: In Singapore, a 'national serviceman' (often abbreviated NS man) refers to a male citizen or permanent resident undergoing compulsory milita.... 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.