Anyone who's ever tried their hand at translating things from another language will tell you that things don't always translate neatly. Sometimes, no word exists in the language your translating to that encapsulates the word you want. I mean, even in English we're missing things. Like, we have no word for people who are no longer virgins (although the Nerdfighter community has proposed Virg-out, which I rather like).
So, this word that is my favorite actually means a few things. But basically δεινος means the terrible, clever, dangerous, wonderful thing. Which is really awesome in my opinion. It's like you are terrible but that terribleness is caused by the cleverness exhibited and this makes you dangerous. And that terrible cleverness leaves others slightly in awe. There's a kind of wonder with that danger and wit.
One of the best examples of this word is The Sphinx. In class readings the Sphinx was described as being δεινος (well, δεινη since she's feminine). And it's not just that she's terrible (which she is. Hello, she eats people who can't answer her riddle) but that she's terrible in her cleverness. It is her clever mind that makes her formidable and horrifying and awe-inspiring. How cool is that?
I know this is short, but I wanted to share my new favorite word with you. And because it's hard to translate to English, I think we just need to steal the word and make it part of our lexicon. Because it is freakin' awesome. And I love it. And we steal words from other languages all the time. What's your favorite foreign word?