雷means shocked by some lowbrow things.It is a funny expression. When a comic hero was shocked by something in the comic book,thunder and lightning would be around his head. 雷人means somebody who often make the common sense mistaken,and the people around him are shocked. ex:An officer has much more property than others,but he said that he was so poor that he couldn't live.So,people know that he just tell a lie,and shocked by the lie.

雷人：2008年兴起的网络语，意思是出人意料且令人格外震惊。这个词语类似晴天霹雳的意思，但又与晴天霹雳不同。晴天霹雳多用于惊闻噩耗的时刻，而雷人则用于表达喜剧性的或无奈性的、尴尬性的场合，将个人感受描述为于无声处听惊雷的状态，极度夸张地表达了个人对喜剧、无奈、尴尬场合中行为和语言的感受。 雷人的本义是云层放电时击倒某人。其网络语言意义兴起于2008年，源出何地无可考证，一说出自浙江某地方言，也有文章称雷人一词是外来语。 “雷人”是 现代词汇的一种新兴用法，即所谓的网络用语，从网络中兴起，目前已经在社会生活中较为广泛的应用，尤其在报纸，杂志等出版物上．形容某人的言谈或行为让人感到很无语，很无奈，很”冷”的效果，使人产生一种被惊吓到的状态，俗称被”雷”到了。

shock,if u are shocked by sth,u can say it 雷人

雷 is verb, literally means thunder, which will astonish people, 人 is people~ it is quite popular net-word, to describe sth unusal and easy to cause surprise and dispute.