Trepid Agonist

Was driving behind a Dodge Intrepid today and got to wondering about the root of that word. Turns out that trepid is a recognized word meaning scared, but that meaning did not come to my mind. Reason? Perhaps because it’s not much used. Intrepid, by contrast, means undaunted, courageous—and, as probably intended by the Chrysler folks, suggests someone with attitude. That in turn led me to search for other words where the negation of the root is common but the root isn’t used anymore. Soon I had a candidate, indeed a talented one, useful both for con and pro. Agonist! Antagonist? Absolutely. Protagonist? Yes, sir. But agonist, meaning a combatant, competitor, actor, or agent—No. Not ever used. There must be other candidates, but my hours-long ‘agonies’ trying to get a Honda tire replaced, unsuccessfully, ended before I had discovered another example. But one thing is certainly true. An agonist, whether anti or pro, whatever the cause, had better be intrepid. Trepid will simply not do.