pozan

1. (of time, season, age) late
   Vratili smo se kući u pozne sate. — We got home in the late hours.
   Doživeo je duboku i poznu starost. — He lived to a ripe old age.
2. (of a period, an artist's work) late
   Ova crkva potiče iz poznog srednjeg veka. — This church dates from the late Middle Ages.

It sounds more literary than kasni and mostly appears in set combinations: pozno veče, pozna jesen, pozni sati.