With little or no preparation or forethought
English: ad-lib, extemporaneous, extemporary, extempore, impromptu, offhand, offhanded, off-the-cuff, unrehearsed
extemporeEnglish
extempore, ad-lib, extemporaneous, extemporaneously, extemporarily
Adjective
Adverb
Without prior preparation
English: extemporaneously, extemporarily, extempore