空有学霸心却是学渣样
[kōng yŏu xué bà xīn què shì xué zhā yàng]
This nickname 'Empty Scholar Heart But Looks Like a Loser' conveys the irony of someone who has the ambition to be an excellent student (a 'scholar') but doesn't achieve that, hence behaving like what is called a 'losers' in China. This term is often used by people self-mockingly to admit their lack of effort and results compared with their expectations.