get above yourself
US /ɡet əˈbʌv jʊərˈself/
UK /ɡet əˈbʌv jʊərˈself/

1.
自命不凡, 得意忘形
to think that you are better or more important than you really are
:
•
After his promotion, he started to get above himself, treating his old colleagues poorly.
升職後,他開始自命不凡,對老同事態度很差。
•
Don't get above yourself just because you won one game.
別因為贏了一場比賽就得意忘形。