What is the term for a performance in which actors make up their lines while on stage?

The term for a performance in which actors make up their lines while on stage is improvisation or theatrical improvisation. Improvisational theater involves spontaneity, creativity, and quick wit, as the actors create scenes, characters, and dialogue on the spot without a pre-written script. Performers rely on their acting skills, teamwork, and audience interaction to create engaging and entertaining theatrical experiences in the moment.