This is the 12th most frequent Croatian word.
nije
"Is not" or "isn't."
The word 'nije' is used here as part of negation in the predicate, denying that the object spoken about belongs to the speaker.
Ovo nije moja knjiga.
This is not my book.
In this sentence, 'nije' negates the attribute of importance attributed to the subject.
Nije važno sada.
It is not important now.
Here, 'nije' disputes the identity of the subject in relation to the context of the object being sought.