This is the 1839th most frequent Polish word.
czeczenii
"Czeczenii" in Polish means "of Chechnya" or "Chechen" in reference to something related to Chechnya or its people.
The word 'Czeczenii' here is in the nominative plural form, referring to people from Chechnya.
Czeczenii walczą o swoją niezależność.
The Chechens fight for their independence.
In this sentence, 'Czeczenii' is in the genitive singular form, denoting the place, Chechnya.
Czytałem o historii Czeczenii.
I read about the history of Chechnya.
Here, 'Czeczenię' refers to the accusative singular, indicating motion towards the region.