From I know, [悪知恵が働く] means "cunning" and [ずる賢い] also means "cunning". Is there any nuances when I use [悪知恵が働く] or [ずる賢い]?
Also for [悪知恵が働く], the kanji 悪知恵 already means "cunning" so why is が働く is used in the phrase. And one more thing that has been bothering me lately, is [悪知恵が働く] always being used to describe something as cunning or is there any other usage of [悪知恵が働く] that I am unaware about