Joya actually means “jewelry”, but when it comes to Argentineans speaking, this word has different uses.
The first one is to say that something is great, or very good.
– ¿Cómo estás, todo bien? (How are you? Everything’s good?
– Sí, sí, todo joya. (Yes, yes, everything is great).
The second one is to agree with something/someone.
– Mañana te doy el dinero que te debo (Tomorrow I’ll give the money I owe you)
– Joya. (OK! or No prob)
“Joya nunca taxi”
This is an idiom that has it origin in used cars salesman. The exact translation would “jewelry never cab”. Doesn’t make much sense, doesn’t it?
Well, what “joya nunca taxi” means is that the car the salesman is showing is so good – even though it’s used – that you’ll never have the need to take a cab because the car broke down.
Some people – not many – use this phrase to say something is really great or is doing really good, not necessarily referring to used cars, of course.
Please, keep in mind that the Y in Argentina sounds like a SH. But I bet you already knew that. 🙂