He held up the trophy with a triumphant smile on his face.

triumphant 是形容词，由名词 triumph（胜利、成功）加上形容词后缀 -ant 构成，表示"胜利的、得意洋洋的"。 triumphant smile 指因获得胜利或成功而露出的自豪、喜悦的笑容。