"Peranakan" means a descendant of the 15th- through 17th-century chinese immigrants to the malay peninsula and nusantara (indonesian archipelago), now part of malaysia, singapore, indonesia, and southern thailand) also known as nanyang. It is one of many casual words teens pick up from friends, social media, music or sport, and on its own it carries no particular warning. If you hear your teen use it, it is fair to ask what they mean by it in their friend group, since meanings drift quickly. Asking out of curiosity rather than alarm tends to keep the conversation open and useful.