Being publicly defeated by his rival left him feeling utterly annihilated.

annihilated 是动词 annihilate 的过去分词形式。annihilate 来自拉丁语，由前缀 ad-（表示"完全"）和 nihil（"无、零"）组成，字面意思是"完全化为乌有"。在句中作表语，表示"被彻底击垮"的心理状态，带有强烈的挫败感和毁灭感。