Verb
To speak extempore; especially, to discourse without special preparation; to make an offhand address.
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.
Source: Webster's dictionaryhe extemporized a speech at the wedding Source: Internet
after the hurricane destroyed our house, we had to improvise for weeks Source: Internet