1. the quality of being determined to continue with something despite difficulties or opposition; stubborn persistence
Usage: formal

Examples

• Her pertinacity in pursuing the research project eventually led to a breakthrough.
• The lawyer’s pertinacity in cross-examining witnesses impressed the jury.
• Despite repeated rejections, his pertinacity in applying for jobs finally paid off.
• The student’s pertinacity in mastering calculus earned her the highest grade in class.
• The detective’s pertinacity in following every lead solved the cold case.
• His pertinacity sometimes bordered on stubbornness, making compromise difficult.