Pertinacious
per-tuh-NAY-shus
Definition
(adjective) Holding firmly to an opinion, purpose, or course of action; extremely persistent.
Example
Despite repeated setbacks, her pertinacious pursuit of the project impressed everyone on the team.
Word Origin
From Latin pertinax, meaning “very tenacious” or “holding fast.”
Fun Fact
Pertinacious is stronger than persistent—it suggests a stubborn, almost unshakeable grip on a goal or belief. Historically, the word was sometimes used critically, implying someone who refused to yield even when logic (or politeness) suggested they should. Today, it often carries admiration: pertinacious people are the ones who push breakthroughs, finish impossible tasks, and stay steady when others waver.