In the corporate world, you are often judged by the people you associate with.

associate 是动词，意思是"交往、联系"，指与某人保持某种关系或往来。 with 在这里是介词，表示"和...一起"，与 associate 搭配使用表示"与...交往"。 associate with 这个短语的意思是"与...交往、与...为伍"，指和某些人保持社交或工作上的往来关系。