Learn how to say Improviser correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word improvise:
create and perform (music, drama, or verse) spontaneously or without preparation:
he invited actors to improvise dialogue
he was improvising to a backing of guitar chords
produce or make (something) from whatever is available:
I improvised a costume for myself out of an old blue dress
early 19th century (earlier (late 18th century) as improvisation): from French improviser or its source, Italian improvvisare, from improvviso ‘extempore’, from Latin improvisus ‘unforeseen’, based on provisus, past participle of providere ‘make preparation for’
Unlike most verbs ending in -ise, improvise cannot be spelled with an -ize ending.