Improvisational (adjective)

1. Relating to or denoting the act of improvising, or making something up on the spot.
2. Relating to or denoting a performance, artwork, or speech that is created spontaneously without preparation.

Origin:

Derived from the word 'improvisation' meaning 'the act of composing, creating, or performing something spontaneously without preparation', 'improvisational' has been in use in english language since 19th century.

Examples:

1. The improvisational comedy show was a hit with the audience.
2. The jazz band's improvisational skills were on full display during the performance.
3. The artist's improvisational approach to painting was praised by the critics.
4. The speaker's improvisational skills helped him deliver a powerful and impactful speech.
5. The improvisational chef's dishes were always unique and inventive.