1. spoken, performed, or composed without advance preparation; impromptu
Usage: formal or literary; often used to describe speeches, remarks, or musical performances

Examples

• The speaker gave an extemporary address that impressed the audience despite having no notes.
• Her extemporary remarks at the ceremony were heartfelt and genuine.
• The jazz musician is known for extemporary solos that showcase his skill.
• He made an extemporary decision to change the route when traffic became heavy.
• The extemporary nature of the debate made it more engaging than a formal presentation.