There are many words that have fallen out of use and been taken up as words in modern media. They can't be copyrighted but they can be trademarked. So words like Sith, Droid, Jedi etc can be used but only if they are used outside the context of the media where they are trademarked. Original creations can be copyrighted, but copyright expires and trademarks don't. You just have to use the trademark to keep it active. Sith is old English, Droid has been used occasionally in the past by other writers, and Jedi is a recognised religion in the US. It's a tangled mess.
If you see something you think breaks the CoC you are more than welcome to pop a ticket in and I'll take a look. It doesn't have to be the full package, it can be the name, costume or bio. Or a combination. I'll make a decision and then act. If in doubt I'll seek advice. I'll also listen to an argument as to why I was wrong and if I am, I will apologise. I have done in the past. Otherwise I'll pass it to the leads to adjudicate. Their decision is final, and contrary to popular opinion will overrule a GM at times. It's rare, but it has happened.