sused

1. neighbour
   Sused iz stana preko puta nam je zalio cveće. — The neighbour from the flat across the hall watered our flowers.
   Susedi su se žalili na buku. — The neighbours complained about the noise.
2. (of a country) neighbour; neighbouring country
   Srbija ima dobre odnose sa susedima. — Serbia has good relations with its neighbours.

In everyday speech komšija is more common; the feminine is susetka.