The term "impromptu" refers to something that is done without prior planning or preparation. It often describes spontaneous actions, speeches, or performances that occur on the spot. For example, an impromptu speech might happen when someone is asked to speak unexpectedly at an event. In social settings, impromptu gatherings can arise when friends decide to meet up without any formal arrangements. These unplanned moments can lead to enjoyable experiences, as they allow for flexibility and creativity. Overall, "impromptu" captures the essence of spontaneity in various situations.