Pristina is the main city of Kosovo, in the western Balkans — the place people mean when they talk about Kosovo’s capital. English usually writes Pristina; in Albanian, the language of most people who live there, it is Prishtina. It is a place name, so you give it a capital letter. You will see it in the news and in geography. Though actually, countries do not all agree whether Kosovo is a country of its own; some dictionaries therefore call Pristina a “regional” capital. The city is real either way. It is not an English common noun, and it has nothing to do with pristine, meaning spotless.