pošast

1. formal pestilence; epidemic; plague
   Kuga je bila najstrašnija pošast srednjeg veka. — The plague was the most terrible pestilence of the Middle Ages.
2. scourge; blight; plague
   Narkomanija je prava pošast među mladima. — Drug addiction is a real scourge among young people.
   Lažne vesti su postale pošast današnjice. — Fake news has become the plague of our time.

In modern usage it is mostly figurative, about social ills.