bigheadedness       
noun [ U ]  disapproving (also big-headedness) uk/ˌbɪɡˈhed.ɪd.nəs/ us/ˌbɪɡˈhed.ɪd.nəs/
 自负的行为
behaviour that shows that you think you are important or intelligent
  Answering questions in class was seen as a sign of big-headedness. 在课堂上回答问题被看作是自负的标志。