Now's a good time to hunt the "uncertain origin" words with roots in the 20th century. We have tools to track their paths and smoke them from their lairs. That's what etymonline has been doing much of the past few months. - D.R.H.
Sometimes, in exasperation, I wrote of such a word, “It has no etymology.” And the words cackled.
A spoken language always wants a handy stock of such words. Words that sound sharp or walk suggestively, crossover words between slang and proper talk; double-head words, hazy words. More than half the meaning in them is how you speak it. They’re like brassy parrots that got free in someone’s suburb and won’t be caught. Peter Pan words, impudently indefined, ahistorical, their footprints slurried in mud.
I read an article in San Diego in the late 80s distinguishing nerd vs. geek. Tech terminology exploded due to PC computers becoming available. Per the article a nerd was a person whose interest was in creating hardware and software. A geek was a person who was not totally experience in how the computer did what it did, but knew how to use it for production of work and to create. My analogy was a race car driver. Nerds build it and maintain it and geeks drive the hell out of it. Since the 80s I have identified as a computer geek.
They’re considered to be of a family. Liberman’s entry on them is extensive. He has a good eye on these sort of amorphous word-sound-clouds. (The column here is more about the modern sense development; the etymology itself is vast.)