"Curiosity killed the cat" is just a saying. And it actually continues as "...but satisfaction brought it back." So it means curiosity is a good thing. I guess you could just simply say "Curiosity is a bad quality" or "Curiosity isn't a good quality to have". The word "quality" can be either good or bad so you have to specify. I hope this makes sense!
It makes sense :) thank you Actually in French, we have an expression which says that "la curiosité est un vilain défaut" which mean that curiosity is a bad thing Défaut is the contrary of a quality in French So I thought I could say a similar sentence in English