(rare) Alternative form of improvisation

To perform improv.

(informal) Improvisation. / (acting) A form of live entertainment characterized by improvisation and interaction with the audience.

present participle of improve

That tends to improve someone or something (especially (dated) to educate or morally better a person).

Capable of being improved. / Capable of being used to advantage; profitable.

Impossible to prove.

Quality of being improvable; capability of improvement.

So as to permit improvement. / In a way that cannot be proven.

plural of improvization