extemporaneous

/ษ™ksหŒtษ›mpษšหˆeษชni.ษ™s/
adjective
  1. 1

    Without preparation or advanced thought; offhand.

    โ€œ"The lovely words of a prepared speech however cannot erase extemporaneous words and deeds โ€” thousands of them โ€” that have run contrary to those aspirations.โ€โ€

Source: https://en.wiktionary.org/wiki/extemporaneous