1. arising from a momentary impulse
2. produced without human planning or labor
3. (of a person) given to acting upon sudden impulses.
4. proceeding from natural feeling or native tendency without external constraint
1. This will not be an entirely spontaneous occasion: a program will be compiled about a week ahead.
2. Questions should be carefully planned but appear spontaneous during the session.
3. I had long ago planned to go the movie , but instead had to go to the park due to a last minute spontaneous decision