Nassim Taleb, on a recent episode of Econtalk, talks about his upcoming book that aims to coin the word antifragility. The essential meaning is close to the phrase “What doesn’t kill you makes you stronger” — a system or process that benefits from volatility, stress, or uncertainty. Examples:
Human bones are antifragile; they benefit from the stress of gravity and weaken without it.
In terms of forest fires, forests are antifragile — too much firefighting can cause more damage in the long run.
Taleb writes about why he needed the word:
So let us coin the appellation "antifragile" for anything that, on average, (i.e., in expectation) benefits from variability. Alas, I found no simple, noncompound word in any of the main language families that expresses the point of such fragility in reverse. To see how alien the concept to our minds, ask around what's the antonym of fragile. The likely answer will be: robust, unbreakable, solid, well-built, resilient, strong, something-proof (say waterproof, windproof, rustproof), etc. Wrong — and it is not just individuals, but branches of knowledge that are confused by it; this is a mistake made in every dictionary.
In short, words like robust and resilient don’t suggest favorability toward adverse conditions.
My question: is there a better word that exists?
Extremophile
is about as close as I could come up with, and that's a pretty specific term, but one could come up with an adjective out of it. I don't think he's quite right though, it's not that they benefit from stress, but instead that they benefit from the environment and circumstances which they evolved to cope with, and indeed, often cannot survive well or at all without that environment because they don't have the mechanisms to cope with the new stuff, even if it may seem less stressful.