Extemporize

Webster's Dictionary of the English Language

·vi To speak extempore; especially, to discourse without special preparation; to make an offhand address.

II. Extemporize ·vt To do, make, or utter extempore or off-hand; to prepare in great haste, under urgent necessity, or with scanty or unsuitable materials; as, to extemporize a dinner, a costume, ·etc.