- Today's Word
Pertinacious
[per-tuh-NAY-shus]
Definition
- (adjective) Someone who is stubbornly persistent or determined, often to the point of being unyielding. It refers to holding firmly to a purpose, belief, or course of action, sometimes even in the face of opposition or difficulty.
Example
The pertinacious reporter refused to drop the investigation, following leads for months until she finally uncovered the truth about the corporate scandal.
Fun Fact
“Pertinacious” comes from the Latin “pertinax,” combining “per-” (meaning “through”) and “tenax” (meaning “tenacious” or “holding fast”). In ancient Rome, being called “pertinax” could be either a compliment or an insult – it praised determination but could also suggest pig-headedness. Interestingly, there was even a Roman Emperor named Pertinax who ruled briefly in 193 CE; he earned his name from his stubborn military leadership style before becoming emperor. The word gained particular significance during the Scientific Revolution, where “pertinacious investigation” became a praised quality among researchers who needed to persist through years of careful study. In psychology, “pertinacity” is studied as a personality trait distinct from mere stubbornness because it involves purposeful persistence rather than simple resistance to change. The term maintains a somewhat formal and literary tone, often carrying a more positive connotation than similar words like “stubborn” or “obstinate.”
(adjective) Capable of producing the desired result; successful in achieving the intended outcome.
The new treatment proved remarkably efficacious in clinical trials, reducing symptoms in over ninety percent of patients within the first two weeks.
Efficacious derives from the Latin efficax, meaning “powerful” or “effectual,” rooted in efficere — “to bring about” or “to accomplish” — built from ex- (“out”) and facere (“to make” or “to do”). The same root gives us effect, efficient, and efficacy — a family of words all built around the idea of something being done and producing a result. It entered English in the 16th century, used predominantly in medical and philosophical contexts to describe remedies or arguments that actually worked.