This is the 8364th most frequent Polish word.
pieni臋偶nej
It seems there was a typo in the word "pieniężnej." If you meant "pieniężnej," it translates to "monetary" or "related to money" in English.
Here, 'pieniężna' is used figuratively to describe the book as being valuable or lucrative, possibly earning money or containing financial wisdom.
Książka, którą przeczytałem, była naprawdę pieniężna.
The book I read was truly lucrative.
In this sentence, 'pieniężnych' refers directly to financial or monetary aspects, describing revenues in terms of money.
Firma poszukuje nowych sposobów na zwiększenie przychodów pieniężnych.
The company is seeking new ways to increase monetary revenues.
The term 'pieniężne' here is used to describe 'funds', emphasizing money in the physical or liquid form.