too big for your britches
US /tuː bɪɡ fɔːr jʊər ˈbrɪtʃɪz/
UK /tuː bɪɡ fɔːr jʊər ˈbrɪtʃɪz/
1.
生意気な, うぬぼれた
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.
昇進して以来、彼は生意気になっている。
•
Don't get too big for your britches just because you won one game.
たった1試合勝っただけで生意気になるな。