Diss song means: A song or hip-hop track, frequently as part of a hip-hop feud, primarily intended to verbally assault or insult a person or a group of people.. It is informal slang, fine in casual speech but not suited to formal contexts. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.