1. In a way that is natural, instinctive, or unplanned; without external cause or stimulus
She spontaneously decided to take a trip to Paris.
Ela decidiu espontaneamente fazer uma viagem para Paris.
2. In a manner occurring or produced without being planned or forced
The audience spontaneously applauded after the performance.
O público aplaudiu espontaneamente após o desempenho.
3. Naturally and without conscious effort or deliberation
The children laughed spontaneously at the joke.
As crianças riram espontaneamente da piada.