0 past simple and past participle of extemporize
1 to speak or perform without any preparation or thought:
So he extemporized by inserting the names of prominent cities of his own time.
A short melody extemporized in a moment of extraordinary emotion is, if impressive, soon taken up by others, further diffused, and traditionally preserved.
As they danced, they sang, either set songs or extemporized ones, sometimes in unison, sometimes in refrain, repeating the verse sung by the lead dancer.
This extemporized action struck the citizens who began to recall it yearly.
It's completely extemporized, as well, most of it.
Armstrong's solos went well beyond the theme-improvisation concept, and extemporized on chords, rather than melodies.