His withering remarks left her feeling utterly humiliated.

withering 是动词 wither 的现在分词形式作形容词用。wither 本意是"枯萎、凋谢"，引申为"使衰弱、使失去活力"。 withering remarks 指那些像使植物枯萎一样能打击人精神的尖锐批评，即"尖刻的评论"。