extempore

/ik-ˈstem-pə-(ˌ)rē/

borrowed from Latin ex tempore "on the spur of the moment, on impulse," from ex "out of, from" + tempore, ablative of tempus "time, the circumstances existing at a particular time, occasion, moment"

adverb or adjective

  1. in an extemporaneous manner

speaking extempore