His friends teased him for being swotty because he always brought textbooks to parties.

swotty 是由动词 swot（用功学习）加上形容词后缀 -y 构成的形容词。swot 本身是英式俚语，指"刻苦学习的人"或"书呆子"。 swotty 形容一个人过分专注于学习，带有贬义色彩，相当于中文里的"书呆子气的"或"死读书的"。