avet

1. ghost; apparition
   Kažu da u toj staroj kući noću luta avet. — They say a ghost wanders that old house at night.
2. (of a person) a pale, gaunt person; a shadow of oneself
   Posle bolesti izgleda kao prava avet. — After his illness he looks like a ghost.
3. formal (figurative) specter
   Nad regionom se ponovo nadvila avet rata. — The specter of war once again loomed over the region.

The noun is feminine: ta avet, strašna avet.