原谅我面无表情看着你装逼
[yuán liàng wŏ miàn wú biăo qíng kàn zhe nĭ zhuāng bī]
This username can be seen as sarcastic. It means 'Forgive me for looking at you with a straight face (no expression) while you show off'. In Chinese culture, someone may put up an expressionless appearance in front of arrogant acts. Thus it is also considered as mocking someone's pretension to others