1. An exciting or intense event, especially a closely contested game or competition.
Usage: informal; chiefly North American
2. A person or thing that is remarkable, impressive, or outstanding.
Usage: informal; chiefly North American

Examples

• Last night's playoff game was a real barnburner—the score was tied until the final seconds.
• The championship match turned out to be a barnburner that kept fans on the edge of their seats.
• That new restaurant is a barnburner; everyone in town is talking about it.
• The debate was a barnburner, with both candidates delivering powerful arguments.
• She delivered a barnburner of a performance that earned her a standing ovation.
• The concert was a barnburner from start to finish.