improvise verb definition in Live music topic from the Oxford Advanced Learner's Dictionary

improvise

 verb: Live music topic
[intransitive, transitive] to invent music, the words in a play, a statement, etc. while you are playing or speaking, instead of planning it in advance ‘It'll be ready some time next week, I expect,’ she said, improvising. improvise on something He improvised on the melody. improvise something an improvised speech