Idioms are not really idiotic, but they don’t make a lot of sense when taken literally. The two words have a common etymology. Idios in Greek means “one’s own, private, unique.” A Greek idiotes was a private person, that is, an uneducated workman or soldier, one who didn’t take part in public affairs like an educated man. You can see how the word came to mean “ignorant,” and developed into our word idiot. An idiom is a word or phrase peculiar to a particular language. English idioms are our own, private, and unique.
I always told my Latin students the following story in order to explain idioms. Our professor in my college French class asked us to write a paragraph in French describing something we had done over the weekend. As he read one student’s effort aloud in front of the class, he stopped short and then began sputtering and laughing over one hapless student’s attempt. When he regained control of himself, the professor explained that the student described a picnic with his family, during which they roasted hot dogs. Hot dogs in French momentarily struck my professor as “dogs in heat” (though the French actually have their own idiom for that). That’s where my professor stopped abruptly until he figured out the English equivalent intended by the student.
Wheelock’s Latin, our text at Cleveland State, introduces idioms with amabo te, literally “I will love you,” which means “please” in Latin. The book’s first example is adapted from the playwright Terence: Da veniam puellae, amabo te, which translates, “Give pardon to the girl, please.” Amabo te implies highly conditional love: Do this for me, and I will love you.
Idioms are vivid and useful, until they become cliches. That’s when we stop noticing how cool they are. “Read between the lines” was at some point startling, but no longer. “He ran off with his tail between his legs” originally created a word picture, but now it’s just trite.
Speaking of tails, Terence provides another of my favorite Latin idioms a few Wheelock chapters later. Auribus teneo lupum in literal English means, “I have a wolf by the ears.” It’s roughly the equivalent of having a tiger by the tail, or being on the horns of a dilemma. Thomas Jefferson once described American slavery as holding a wolf by the ears. He wrote, “We can neither hold him, nor safely let him go. Justice is in one scale, and self-preservation in the other.” Tragic and telling that he saw the dilemma so clearly but never attempted to resolve it.