veseliti

1. (veseliti se) to have fun; to make merry
   Gosti su se veselili do zore. — The guests made merry until dawn.
   Cela ulica se veselila posle pobede. — The whole street was celebrating after the win.
2. (veseliti se + dat.) to be glad about; to look forward to
   Deca se vesele raspustu. — The kids are looking forward to the holidays.
   Nije se baš veselio tom sastanku. — He wasn't exactly looking forward to that meeting.
3. (with direct object) to cheer up; to make happy
   Muzika je veselila goste celo veče. — The music kept the guests in good spirits all evening.

For "to be glad", radovati se is more usual in Serbia.