This is the 625th most frequent Croatian word.
nacionalnog
"National."
The word 'nacionalnog' here is used as an adjective in the genitive singular masculine form, modifying the noun 'identitet' (identity), to describe it as pertaining to a nation.
Održali smo raspravu o značaju nacionalnog identiteta.
We held a discussion about the significance of national identity.
In this sentence, 'nacionalnog' serves as an adjective in the genitive singular masculine form, qualifying the noun 'centra' (center), denoting its national characteristic.
Posjetili smo arhiv nacionalnog muzejskog centra.
We visited the archive of the national museum center.
Here, 'nacionalnog' is again an adjective in its genitive singular masculine form, modifying 'razvoja' (development), indicating that the development pertains to the nation.