1. A spontaneous or hastily organized demonstration of disapproval or objection, typically unplanned and conducted without prior formal organization
The impromptu protest erupted outside the government building after the controversial decision was announced.
O protesto improvisado eclodiu em frente ao prédio do governo após a decisão controversa ser anunciada.
2. A sudden expression of disagreement or opposition, often involving a gathering of people without advance coordination
Students organized an impromptu protest against the tuition increase.
Estudantes organizaram um protesto improvisado contra o aumento das mensalidades.