There’s an old saw that says something like “If you can’t teach it, you don’t really know it.” I’ve been discovering that with my kids lately as we add new words to our wall. Many of them are words that I use and read without difficulty, but when called upon to pinpoint the meaning in a way that is valuable for kids, I’m at a loss more often than I would have thought. By way of teaching myself so I can teach better, let’s look at…
The word history of this one is straight as an arrow. It comes to English without interference from Latin itself where the word itself (same meaning as the modern English version) was insidiosus, from insidiae, meaning “an ambush,” which comes from the verb insidere, “to lie in wait for, to sit upon.”
Wait, what? To sit upon?
Insidere can be broken down into two parts: a common verb and a prefix. The common verb is sedere, which means “to sit.” The prefix is the fun part. Some prefixes, like “re-“, haven’t changed all that much in their journey of two thousand years. Some, however, are a little funky. “In-” is an interesting one, because it comes from a preposition. Without going into the Latin/English quarrel over genuine preposition placement that Churchill famously responded to by quipping: “That is something up with which I will not put,” the relationship of Latin preposition to English prefixes and prepositions is a fun one.
For other crazy word people, I should say. I hate them.
What is interesting about this preposition-turned-prefix we see in “insidious” is that the original Latin preposition can (and often does) mean not simply “inside” or “into” or “toward,” but also “against.” It picks up the sense that when you move toward something, there is likely to be something in your way that must be beaten down or attacked. It is from this deliciously barbaric sense of in- that we get insidere. To sit against someone is to wait to attack them from a lower position, lying in wait, as it were.
Sit-ins have been around for a long time, it would seem, but they weren’t always demonstrations of passive resistance.