unpremeditated; impromptu

plural of improvising

Able to be improvised.

An unconventional or amateur explosive weapon made from nonmilitary components, especially one used by guerillas, commandos or terrorists.

plural of improvised explosive device

A form of improvisational theatre performed with little predetermination of subject matter and structure, but with interaction with the audience. / An instance of such theatre.

a form of theatre in which the actors perform spontaneously, without a script

plural of improvisational comedy