exultant

Very happy, especially at someone else's defeat or failure.

Japanese Meaning

非常に喜んでいる様子、特に他人の敗北や失敗に対して得意げな喜びや満足感を示す

He wore an exultant smile after hearing that his opponent had failed to secure the contract.

彼は、相手が契約を取れなかったと聞いて、勝ち誇ったような笑みを浮かべていた。

Sense（1）

Very happy, especially at someone else's defeat or failure.