swollen-headed       
adjective  informal disapproving uk/ˌswəʊ.lənˈhed.ɪd/ us/ˌswoʊ.lənˈhed.ɪd/
 自命不凡的,自负的,神气活现的
thinking that you are more intelligent or important than you really are
  I didn't know how to mention it without sounding swollen-headed. 我不知道该怎么说才不显得自以为是。 
 See: swollen head
 - More examples
 - They are swollen-headed semi-intellectuals.
 - They have done well, but do not allow them to get swollen-headed.
 - Swollen-headed actors should take note.