This is the 974th most frequent Icelandic word.
vestfirðinga
"Vestfirðinga" means "people of the Westfjords" in Icelandic.
Here, 'Vestfirðinga' is again in the genitive plural, used in the possessive sense relating to their history.
Bókin fjallar um sögu Vestfirðinga á 19. öld.
The book deals with the history of the Westfjord people in the 19th century.
In this example, 'Vestfirðinga' is in the plural accusative form, specifying the direct object of the meeting.
Ég hitti nokkra Vestfirðinga á hátíðinni.
I met some people from the Westfjords at the festival.
In this sentence, 'Vestfirðinga' is used as a genitive plural noun referring to the inhabitants of the Westfjords, showing their collective characteristic.