This is the 791st most frequent Polish word.
istotne
Essential; important.
The word 'istotne' means 'important' or 'significant' and is used here to emphasize the relevance of the question.
To jest bardzo istotne pytanie.
This is a very important question.
The word 'istotnych' is the locative, plural form of 'istotne', describing matters of importance.
W istotnych sprawach zawsze należy być uczciwym.
In significant matters, one should always be honest.
The word 'istotnej' is the genitive, feminine singular form of 'istotne', referring to an 'essential' or 'crucial' aspect.