intransitive and transitive. To improvise, extemporize.

transitive. To compose and perform (music, poetry, drama, etc.) spontaneously or without preparation; to deliver (a speech) extemporaneously.

transitive. To compose on the spur of the moment; to compose and utter off-hand.

To produce (a picture, literary composition, etc.) quickly or impromptu; also to delineate exactly, ‘hit off’.