Synonyms for the phrase "extemporise perform" are abundant, allowing one to express improvisation or spontaneous actions. One alternative term is "improvise," which implies creating or inventing something on the spot without prior preparation. "Ad-lib" is another synonym often used in the context of theater and comedy, referring to actors spontaneously adding lines or actions to a script. Additionally, "wing it" signifies performing without a planned strategy or relying on one's natural abilities. "Fly by the seat of one's pants" conveys embarking on a task without careful planning or predetermined steps. Other synonyms include "spontaneous performance," "make it up as you go along," and "play it by ear," all capturing the essence of extemporising in various situations.