1. An unplanned or spontaneous gathering, performance, or occasion created without prior preparation
The concert turned into an improvised event when the main performer didn't show up.
O concerto virou um evento improvisado quando o artista principal não apareceu.
2. A social or entertainment occasion organized hastily or on short notice
They organized an improvised event in the park for the neighborhood children.
Eles organizaram um evento improvisado no parque para as crianças da vizinhança.