too big for your britches
US /tuː bɪɡ fɔːr jʊər ˈbrɪtʃɪz/
UK /tuː bɪɡ fɔːr jʊər ˈbrɪtʃɪz/
1.
自命不凡, 自高自大, 狂妄自大
acting in a way that shows you think you are more important or capable than you really are; arrogant or conceited
:
•
Ever since he got that promotion, he's been acting too big for his britches.
自從他得到那次升職後，他就開始自命不凡了。
•
Don't get too big for your britches just because you won one game.
不要因為贏了一場比賽就自命不凡。