too big for your boots
自命不凡，傲慢自大
口語·批評自大
英文釋義
to have an exaggerated sense of one's own importance or abilities
例句
Ever since he got that promotion, he's been too big for his boots.
典故來源
源自19世紀(jì)英國，比喻一個(gè)人自視過高，連靴子都裝不下他的傲慢。