Once upon a time (circa 1939), James Thurber made some drawings and Margaret Ernst wrote some words, and they put them all together in a book they called “In a Word.” It was a fun look at the origins of several hundred words. The primary intent was to entertain, but Thurber hoped the book would do a bit more for its readers.
“It is my personal prayer that it will also serve to impress them with the importance of accurate speech, careful writing, and true meaning in a period of the world’s history when those virtues of communication are becoming more and more essential to the security, such as it is, of Man on earth,” he wrote.
For instance, Thurber said, no woman should call another “fastidious” without looking up the meaning. That’s because it comes from the Latin fastidium, or loathing. Something that was fastidious originally meant something that was disgusting. Gradually it came to mean the person who felt disgust. A person who is easily disgusted might be considered squeamish. So the word is often used to mean someone who is a bit too dainty or over-neat. But it’s never a compliment.
“Nincompoop” is never a compliment either, but at least there’s little chance of using it the wrong way. Ernst claims it’s from another Latin original, non compos mentis, or not in possession of one’s mind. Over time it was shortened to non compos and then garbled into it’s present form. (That’s far more than my Webster’s New Universal Unabridged Dictionary has to say about it.)
The book leans heavily on Latin, but the Greeks also get credit for quite a few contributions, one of them being “diplomat,” from their word for doubling. “Everything the career boys do is like a diploma (in its original form) — folded over twice — so you can’t see what’s underneath,” Ernst wrote.
You can see what’s underneath the covers of this book, though, because you can still buy it online even though you have to buy it used. It’s pretty cheap, too.