to compose and perform or deliver without previous preparation; extemporize: to improvise an acceptance speech.
2.
to compose, play, recite, or sing (verse, music, etc.) on the spur of the moment.
3.
to make, provide, or arrange from whatever materials are readily available: We improvised a dinner from yesterday's leftovers.
verb (used without object)
4.
to compose, utter, execute, or arrange anything extemporaneously: When the actor forgot his lines he had to improvise.
Origin: 1820–30; < Frenchimproviser, or its source, Italianimprovisare (later improvvisare), verbal derivative of improviso improvised < Latinimprōvīsus, equivalent to im-im-2 + prōvīsus past participle of prōvidēre to see beforehand, prepare, provide for (a future circumstance). See proviso
1826, from Fr. improviser (17c.), from It. improvisare "to sing or speak extempore," from improviso, from L. improvisus "unforeseen, unexpected" (see improvisation).