nezgoda

1. accident; mishap
   Na raskrsnici se dogodila saobraćajna nezgoda. — There was a traffic accident at the intersection.
   Imao je nezgodu na poslu i slomio ruku. — He had an accident at work and broke his arm.
2. trouble; misfortune; inconvenience
   Nezgoda je u tome što nemam ključ. — The trouble is that I don't have a key.

"Saobraćajna nezgoda" is the official term for a traffic accident; "nesreća" usually sounds more serious.