Thanks for the list. If I may trouble you a little further, do you know of any that are older? The oldest one on this list, according to Exapno’s link, is goober, from 1833. Do you know of any words that seemed to have popped into existence at an earlier time?
“Dog,” given in the post just before yours, came out of nowhere in Old English, although it was rare until the time of Middle English. It’s harder to be certain that a word has no apparent etymology the further back it first appeared. That’s what makes me reluctant to answer your question directly. The further back that a word first appeared, the more likely it is that there’s some probably some bogus etymology that someone has proposed somewhere that is almost certainly wrong but which is hard to definitively disprove because we don’t understand the context of the times. There are words, for instance, which appear in Proto-Germanic but which don’t appear in Proto-Indo-European. Is this an example of what you’re looking for? What does that prove except that we don’t know much about how the people of 6000 B.C. through 1000 B.C. spoke?
On the other hand, it’s more interesting to etymologists that there are words and phrases which appeared within the past fifty years and yet which have no established etymology. Once again, look up the threads on the phrase “the whole nine yards.” An enormous amount of effort has been expended on researching it. If you can definitively establish its origin, you will win the Nobel Prize for Etymology. (Well, you would if there was a Nobel Prize for Etymology, but Alfred Nobel’s wife had an affair with an etymologist, so he didn’t create such a prize.) All the printed material of the time is available, many of the people who used it are still alive, and yet it still seems to have come out of nowhere in the 1960’s. There are lots of bogus etymologies floating around that can be disproved, sometimes rather easily. There are some interesting clues (such as that there seems to be some connection to the U.S. Airforce in the 1960’s) which we can’t quite fit into a complete explanation for it.
I’ve never heard or seen this one before – had to look it up. Is it regional?
I’d always assumed “quiz”, in the sense of a series of questions, was short for “inquisition”. But nobody even seems to have considered that, or at least I can’t find any discussion on the internet about it…
Copacetic (I just learned this word from another thread).