импровизация означава в английски

impromptu▼(any composition, musical or otherwise, that is created on the spot without preparation)
noun
[UK: ɪm.ˈprɒmp.tjuː] [US: ˌɪm.ˈprɑːmp.tuː]

improvisation [improvisations]▼(act or art of composing and rendering music, poetry, and the like, extemporaneously)
noun
[UK: ˌɪm.prə.vaɪ.ˈzeɪʃ.n̩] [US: ˌɪmpra.və.ˈzeɪʃ.n̩]