improvisation (n.)youdaoicibaDictYouDict[improvisation 词源字典]
mid-15c., "unforeseen happening;" 1786 as "act of improvising musically," from French improvisation, from improviser "compose or say extemporaneously," from Italian improvvisare, from improvviso "unforeseen, unprepared," from Latin improvisus "not foreseen, unforeseen, unexpected," from assimilated form of in- "not, opposite of" (see in- (1)) + provisus "foreseen," also "provided," past participle of providere "foresee, provide" (see provide).[improvisation etymology, improvisation origin, 英语词源]