Extemporal is a word that refers to something that is done without preparation or planning. There are several synonyms for the word extemporal that one can use depending on the context. Some of these synonyms include impromptu, extemporaneous, improvised, spontaneous, and off-the-cuff. These words all convey a sense of improvisation or something done without planning. For example, an impromptu speech is one that is given without prior preparation, while an extemporaneous performance is one that is done without a script or preplanned choreography. Using these synonyms can add variety and nuance to one's writing or speech, and help to convey the desired meaning more clearly.