improvisate
/ˈɪmprəvʌɪzeɪt/ /(ˌ)ɪmˈprɒvɪzeɪt/rare after late 19th cent
verb
[with object] And without object. To compose or perform (poetry, drama, music, etc.) spontaneously; to extemporize (a speech, lecture, etc.).
Origin
Early 19th century. From French improviser and its etymon Italian improvvisare + -ate, after improvisation, improvisator, etc.