Is this the thread where we post our dumb kid etymologies? Because oh boy, I've got one.
CW: SA
As a kid, I played a lot of Ogre Battle 64. One of the weapons in the game is called a rapier. I'd never heard of them before and wasn't familiar with the word, but one day I happened to overhear some true crime thing my mom was watching on TV that involved rape. I also did not recognize this word, but I gleaned from context that it was a violent sex thing.
Aha! The light went off in my dumb kid brain. To rape someone meant to stab them in the junk, and a rapier was a sword designed specifically for doing so.