give oneself airs 摆架子，装腔作势，耀武扬威

【例句】
I got tired of seeing all my old classmates giving themselves airs as though they were important or wealthy or something.
我厌倦了看到我所有的老同学装腔作势，好像他们很重要、很有钱什么的。

I dislike Helen now. She is always giving herself airs.
我现在很讨厌海伦，她总是装模作样。