opako

1. wickedly; maliciously; viciously
   Pas je opako zarežao na nas. — The dog growled at us viciously.
   Ta rana izgleda opako. — That wound looks nasty.
2. colloq. (as an intensifier) seriously; terribly; really
   Napolju je opako hladno. — It's seriously cold outside.
   Ovaj bend svira opako dobro. — This band plays wickedly well.