Dostoevsky anyone?

I don't know Russion very well but Polish, which is also a Slavic language, is my mother tongue and I can often guess the meaning of the Russion words accurately.

As for zloy, 'злой', this word is very similar to the Polish word 'zły'. I've checked it in the dictionary to be sure and it has confirmed what I strongly suspected.

If I had to translate this word, I would choose 'evil'. As I see that in English 'evil' has also some connection to religion, spirit - from Oxford Dictionary - (of a force or spirit) embodying or associated with the forces of the devil

And this is a strong association. If something or someone is 'zły' - 'evil' it or that person has something satanic to it, is immoral.

This is the primary meaning of this word but the Polish 'zły' has many meanings and one of them is that someone who is 'zły' is outraged, angry, irritated, annoyed, so it is possible that the Russian 'злой' can also be used like that.

I have also checked 'злоба', which is transliterated as 'zloba' and this made me immediately think of the Polish word 'złość'. If I had to translate it, I would chose - anger, outrage, annoyance, irritation.

In conclusion, it is likely that one of the meanings of the adjective 'злой', is synonymous with the primary meaning of the noun 'злоба' but it's not the primary meaning of 'злой'.