If you use it enough...

Because I was actually familiar with every word used in today's Big Ten Wonk post, the Word Of The Day will be a Wonk favorite:

indefatigable adj. showing sustained enthusiastic action with unflagging vitality. (more)

I believe the intent of the word is to emphasize passion and dedication, not endurance. Unfortunately, an alternate definition -- simply "tireless" -- is much more readily assumed by the unfamiliar reader upon first encountering the word. At least, that's how I first interpreted it last spring. What the word has going for it, though, is that it's slightly obscure enough to make one wonder, "Is that what it really means?"