Nuances between 悪知恵が働く and ずる賢い and clarifications for 悪知恵が働く


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




悪知恵 means ”bad wisdom”. So, 悪知恵が働く means ”bad wisdom is working”. It may be
more appropriate to translate ”doing evil deed come into my mind” or merely
”doing evil deed”, than ”cunning”.

On the other hand, ずる賢い means ”dishonest and clever”. It mostly use towords
people.

”悪知恵が働く **人** ” and ”ずる賢い” means almost the same thing.

