Years of loneliness had hollowed her out, leaving her emotionally drained.

hollowed 是动词 hollow 的过去分词形式。hollow 本意是"使...变空、挖空"，引申为"掏空、耗尽"的意思。这里用过去分词形式表示被动完成的状态，描述"内心被掏空"的持续效果。