Extemporaneous (adjective)

Performed or spoken with little or no preparation; impromptu.

Origin:

From the latin extemporaneus, from ex- "out of" + tempus "time".

Examples:

1. The speaker delivered an extemporaneous speech without any notes or script.
2. The actor gave an extemporaneous performance, improvising his lines throughout the scene.
3. The chef's extemporaneous dishes were created on the fly, using whatever ingredients were on hand.
4. The singer's extemporaneous rendition of the song was both surprising and impressing.
5. The extemporaneous lecture was filled with insights and anecdotes that were not in the script.