večit

1. eternal; everlasting
   Obećali su jedno drugom večitu ljubav. — They promised each other eternal love.
2. perpetual; constant
   Dosta mi je tvojih večitih izgovora. — I'm sick of your constant excuses.
   On je večiti student, studira već deset godina. — He's a perpetual student, he's been studying for ten years.

Večit and večan are near-synonyms; for 'constantly recurring' večit is more usual.