brlog

1. den; lair; burrow
   Medved celu zimu spava u brlogu. — The bear sleeps in its den all winter.
2. colloq. derog. (of a room or flat) pigsty; dump; hovel
   Sredi sobu, ovo je pravi brlog! — Tidy your room, it's a real pigsty!
3. derog. (of a person's dwelling or hideout) lair; den; hideout
   Policija je otkrila brlog lopova na periferiji. — The police found the thieves' lair on the outskirts.

Applied to a person's dwelling or hideout, the word is always disparaging, sometimes humorous.