"chac-chac" means: A type of rattle used in the traditional music of Grenada and Trinidad and Tobago; it is made from a gourd and used to provide a rhythm.. 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.