This is the 306th most frequent Polish word.
nią
The Polish word "nią" means "her" and is used as the instrumental case form of "ona" (she).
The word 'nią' is the instrumental case of 'ona' (she), expressing accompaniment or means of action in the prepositional phrase 'z nią', meaning 'with her.'
Widzę ją i chcę rozmawiać z nią.
I see her and want to talk with her.
'Nią' is the instrumental case governed by the preposition 'za,' which here indicates following or pursuing.
Podążam za nią przez park.
I follow her through the park.
In this usage, 'nią' is the instrumental case object of the verb 'opiekuję się' (I take care of), as the verb requires the object to be in the instrumental case.