1. in a manner done or made without advance preparation; impromptu or off-the-cuff
Usage: formal; often used in academic or professional contexts

Examples

• The speaker addressed the audience extemporarily after the prepared remarks were cut short.
• She performed the piano piece extemporarily, without sheet music or rehearsal.
• He extemporarily composed a poem for the wedding toast.
• The jazz musicians played extemporarily, creating new melodies on the spot.
• The teacher extemporarily adjusted the lesson plan based on student questions.