nerd          
noun [ C ]  informal disapproving uk/nɜːd/ us/nɝːd/
 蠢货,呆瓜(尤指男子)
a person, especially a man, who is not attractive and is awkward or socially embarrassing
  He was a real nerd in high school - I can't believe he's so handsome now. 他上高中的时候呆头呆脑——我简直无法相信他现在这么帅。 
  对(尤指计算机)入迷的人
a person who is extremely interested in one subject, especially computers, and knows a lot of facts about it
  I'm a real grammar nerd. 我真的是一个语法迷。