adio

1. colloq. kiss it goodbye; so long
   Ako te šef uhvati, adio posao! — If the boss catches you, you can kiss your job goodbye!
   Pozajmio sam mu pare i adio. — I lent him money and that was the last I saw of it.
2. colloq. humor. goodbye; farewell
   Adio, drugari, vidimo se na leto! — Farewell, guys, see you in the summer!

As a farewell it sounds jokey or coastal; in Belgrade it more often means something is lost for good.