šupalj

1. hollow; with a hole
   Deca su se sakrila u šuplje drvo. — The kids hid in a hollow tree.
   Opet imam šuplju čarapu. — I've got a hole in my sock again.
2. (of a tooth) decayed; with a cavity
   Zubar kaže da imam dva šuplja zuba. — The dentist says I have two cavities.
3. colloq. (of words, promises) empty; hollow
   To su samo šuplja obećanja pred izbore. — Those are just empty pre-election promises.