Flashmob is a term that refers to a group of people who assemble suddenly in a public place and perform an unusual or seemingly spontaneous act. However, there are many other synonyms for flashmob that have emerged over time. One popular synonym is "guerrilla gathering," which refers to a group of people who gather in a public space and perform an unexpected action. Another synonym that has gained popularity is "happening," which describes a spontaneous, unstructured performance or event. Other synonyms for flashmob include "instant gathering," "improv group," and "spontaneous dance party." Regardless of what you call it, a flashmob is an exciting and unique way to bring people together for a fun and unexpected experience.