1. in a way that shows stubborn or persistent determination; with firm adherence to a purpose or belief despite difficulty or opposition
Usage: formal; often implies admirable persistence, but can suggest unreasonable stubbornness depending on context

Examples

• She pertinaciously pursued her dream of becoming a doctor despite years of rejection.
• The lawyer pertinaciously argued the case, refusing to accept defeat.
• He pertinaciously held to his beliefs even when everyone disagreed with him.
• The researcher pertinaciously investigated the problem until she found a solution.
• They pertinaciously continued their efforts to save the endangered species.
• The athlete pertinaciously trained every day to improve her performance.