Constant criticism has left him desensitized to other people's opinions.

desensitized 是动词 desensitize 的过去分词形式。desensitize 由前缀 de-（表示"去除、减少"）和 sensitive（敏感的）组成，字面意思是"使敏感性降低"。在句中表示"变得麻木、不再敏感"的状态。