glavonja

1. colloq. humor. man with a large head
   U školi su ga zvali glavonja. — At school they called him Bighead.
2. colloq. derog. (usually in plural) bigwig; big shot; fat cat
   O tome odlučuju glavonje u ministarstvu. — That is decided by the bigwigs in the ministry.
   Partijske glavonje su se sastale iza zatvorenih vrata. — The party bigwigs met behind closed doors.

In the sense 'bigwig, big shot' the word is usually used in the plural (glavonje) and with a dismissive tone.