1. the quality of being feisty; liveliness, spiritedness, or bold confidence, especially in a small or seemingly weak person or animal
Usage: informal; often positive connotation
2. a tendency to be quarrelsome, irritable, or combative
Usage: informal

Examples

• The small dog showed remarkable feistiness when defending its territory.
• Her feistiness and determination helped her succeed despite the obstacles.
• The candidate's feistiness during the debate impressed many voters.
• He was known for his feistiness in standing up to authority.
• The team's feistiness in the second half led to an unexpected comeback.
• She displayed feistiness by refusing to back down from her principles.