jub ‧ i ‧ lant /ˈdʒuːbələnt, ˈdʒuːbɪlənt/ BrE AmE adjective
[ Date: 1600-1700 ; Language: Latin ; Origin: present participle of jubilare 'to call out, shout because you are happy' ]
extremely happy and pleased because of a success:
Radicals were jubilant at getting rid of him.
The fans were in jubilant mood as they left the stadium.
—jubilantly adverb