After his promotion, he started behaving like a nawab, bossing his colleagues around.

nawab 源自印度乌尔都语，原指印度莫卧儿帝国时期的地方行政长官或穆斯林王公贵族，拥有很大权力和财富。在现代英语中常用来比喻"摆出高高在上姿态的人"，带有讽刺意味，形容某人获得权力后表现得傲慢专横。