She held the trophy triumphantly above her head, showing it to the crowd.

triumphantly 是形容词 triumphant 的副词形式，由 triumph（胜利）加形容词后缀 -ant（表示"具有...性质的"）构成形容词，再加副词后缀 -ly 构成副词。triumphantly 表示"胜利地、得意洋洋地"，形容以胜利的姿态或情绪做某事。