1. holding firmly to an opinion or course of action; stubbornly persistent
Usage: formal

Examples

• The pertinacious lawyer refused to give up on the case despite numerous setbacks.
• Her pertinacious efforts to master the violin finally paid off after years of practice.
• The pertinacious student kept asking questions until she fully understood the concept.
• His pertinacious pursuit of justice made him both admired and criticized.
• The pertinacious negotiator would not accept any compromise on the key terms.
• Despite facing rejection after rejection, the pertinacious writer continued submitting her manuscript.