egg head（也写作egghead）最早出现于1907年，最初本义指秃头的人，因用脑过度头发掉光而秃头，其头部形状圆润酷似鸡蛋而得名。1918年，该词被芝加哥新闻从业者首次赋予引申义，用来指代知识分子；1952年，美国专栏作家斯图尔特·阿尔索普在总统竞选报道中大量使用该词，调侃候选人阿德莱·史蒂文森及其支持者，使其贬义用法彻底普及，成为英语中经典俚语。

现其核心语义多含贬义，也可带幽默调侃语气，核心指：过分沉迷书本、理论研究，缺乏实际生活经验、不懂人情世故的书呆子、学究、高级知识分子，侧重强调其人重理论轻实践、脱离现实的特点。

如：

He was regarded as an egg head by his classmates, for he only read books and never joined in outdoor activities.

他被同学称为书呆子，因为只知道读书而绝不参加户外活动。

The silly egg head didn't realize his girlfriend was angry until she left.

那个傻书呆子直到女朋友离开了才知道她生气了。

He is such an egg head that he never knows how to please his girlfriend in daily life.

他就是个彻头彻尾的书呆子，从来都不知道在日常生活中如何讨好自己的女朋友。

She broke up with the egg head because he only cared about his research and ignored her feelings.

她和那个书呆子分手了，因为他只在乎自己的研究，完全忽略了她的感受。

That egg head can't even understand the romantic hints his crush gives him.

那个书呆子就连心仪对象给他的浪漫暗示都完全看不懂。

The egg head teacher always focuses on theoretical knowledge but neglects practical teaching.

这位书呆子老师总是只注重理论知识，却忽视实践教学。

The politician mocked the policy advisors as a group of egg heads who are out of touch with public opinion.

这位政客嘲讽政策顾问们是一群脱离民意的书呆子。

These economic egg heads' theories often fail to apply to real market operations.

这些经济学书呆子的理论，往往无法适用于真实的市场运作。

The military commander refused to take the egg head's impractical battle plan.

军事指挥官拒绝采纳这个书呆子不切实际的作战计划。

Diplomatic work needs flexibility, and egg head-style thinking will easily lead to negotiation deadlock.

外交工作需要灵活变通，书呆子式的思维很容易导致谈判陷入僵局。

Don't be such an egg head, Leonard! You should go on a date instead of studying physics all night.

别这么书呆子气，伦纳德！你该去约会，而不是整晚研究物理。《生活大爆炸》

Ross is a total egg head when it comes to paleontology, he can't even chat with girls normally.

罗斯一涉及古生物学就完全是个书呆子，他甚至都没法正常和女生聊天。《老友记》