If you refer to the vacuity of something or someone, you are critical of them because they lack intelligent thought or ideas.
例句
His vacuity was a handicap in these debates.在这些辩论中，思想贫乏是他的一个弱点。...a campaign notable for its intellectual vacuity and personal nastiness.以思想空洞和人身攻击闻名的竞选活动