Improvisation is the act of creating or performing something without planning or preparation. It means making things up as you go along. Full definition
After he'd gotten this bit of improvisation out of his system, he produced more sculpture, now with a furniture maker's skill and finesse, and he started painting again, bringing experimental materials to both mediums. (nytimes.com)
With Thirst Street there was a lot of improvisation in terms of the dialogue. (theseventhart.org)
Troupe members also leave room for improvisation in their presentations. (educationworld.com)