Since her promotion, she's become quite uppity and doesn't even respond to old friends' greetings.

uppity 是由 up（向上）加上后缀 -ity 构成的形容词，字面意思是"高高在上的"。这个词带有贬义，形容某人因为地位提升而变得傲慢自大、看不起他人，常用来描述那些突然获得权力或地位后就态度傲慢的人。