The word "most unspontaneous" refers to something that lacks liveliness or enthusiasm. On the other hand, its antonyms could be lively, enthusiastic, animated, spontaneous, enthusiastic, and vivacious. These words indicate a burst of excitement, energy and zest. Antonyms of "most unspontaneous" suggests something full of vigor, excitement and vigor. Such things entail creativity, spirit, zeal and drive. These words describe anything that exudes liveliness and energy. They are often used to describe an ebullient personality or upbeat environment. While "most unspontaneous" might retain a more negative connotation, its antonyms are much more positive and optimistic.