"Australia" means "southern". Before it was found by Europeans, it was suspected that a continent exists there, and it was tentatively named "terra australis incognita", which means "unknown land in the south", and "australis" was the Latin word for "south".
Should be noted that "China" comes from the word "Qin" whereas "Central Nation" is referring to "Zhongguo". It'd be like giving the etymology of "Holland" when the answer is "Netherlands".
Oi, Josh ~ I gotta call this one your first swing-and-a-miss. An unsourced imgur graphic is not a good authority on which to base anything; a quick perusal of Wikipedia (itself not even worthy of being a primary, unverified source for quizzes, IMHO) shows that nearly every hint here is wrong. I do love the idea though! With proper research, I think it could turn out to be a pretty funny quiz (for instance, Sri Lanka's actual, correct literal English translation of "Mr. Island" inexplicably gives me the giggles). Anyway, I was delighted to find your quizzes through your first featured one (congrats!), and honestly, I think you already have some gems that could be featured-worthy with just a bit of polishing up. I love the way your mind works!!