ex ‧ tem ‧ po ‧ ra ‧ ne ‧ ous /ɪkˌstempəˈreɪniəs◂/ BrE AmE adjective formal
[ Date: 1600-1700 ; Language: Late Latin ; Origin: extemporaneus , from Latin ex tempore ; ⇨ ↑ extempore ]
spoken or done without any preparation or practice SYN impromptu :
an extemporaneous speech
—extemporaneously adverb