nafta

1. oil; petroleum
   Cena nafte na svetskom tržištu ponovo raste. — The price of oil on the world market is rising again.
2. colloq. (at a gas station) diesel fuel
   Moj auto ide na naftu, ne na benzin. — My car runs on diesel, not petrol.
   Sipao sam naftu za dve hiljade dinara. — I put in two thousand dinars' worth of diesel.

At a gas station nafta usually means diesel; petrol is benzin.