“The corruption of Chinese women has resulted in the fall of the nation,” proclaimed Yu Minhong, founder and president of the New Oriental Education & Technology Group, at November’s “Power of Learning” forum. Yu’s thundering condemnation precipitated an online storm of words about gender equality and misogyny in Chinese society.

Why would a well-educated and successful entrepreneur, who rose from a poor rural background to found China’s first SAT-prep corporation listed on the New York Stock Exchange, air such ignorant views? How could the man who inspired the 2013 hit film American Dreams in China hold such nightmare opinions? Disapproving netizens concluded that Yu must be 膨胀 (“inflated,” péngzhàng)—in other words, conceited, or swelled up with success.

The origin of the expression can be understood from physics. Just as air expands after it’s heated, so can a person puff up from too much flattery. It’s an attitude that goes against the traditional Chinese virtue of modesty, and has been warned against throughout history: “Complacency incurs losses, and modesty benefits,” advises the Eastern Jin dynasty’s (317 – 420) Classic of History, while Mao Zedong claimed that “Modesty makes one progress, whereas conceit makes one lag behind.”

Nowadays, “inflated” or “self-inflated” can playfully refer to one’s sense of pride. Chinese actor and director Dong Chengpeng, for example, claimed, “I’m not inflated, and still play mahjong for pocket change (我没有膨胀，还玩儿5毛钱的麻将。 Wǒ méiyǒu péngzhàng, hái wánr wǔ máo qián de májiàng)” after his 2015 movie A Hero or Not made 1 billion RMB at the box office. A fan of TFBoys’ Wang Yuan once commented, after reading an article about their boy band idol, “Media everywhere is praising our boy; the more I read, the more inflated I feel. (媒体都在夸我们王源，越看越膨胀。Méitǐ dōu zài kuā wǒmen Wáng Yuán, yuè kàn yuè péngzhàng.)”

It is also used to mock (or self-mock) any unrealistic behavior, as in “I just said that a villa costing 8 million RMB was cheap. I must be getting inflated! (感觉自己膨胀了，竟然敢说一个八百多万的别墅真便宜！Gǎnjué zìjǐ péngzhàng le, jìngrán gǎn shuō yī gè bā bǎi duō wàn de biéshù zhēn piányi!)”

Individuals full of hot air may become unmoored from everyday thinking, and start flying away—or  飘了 (“floating,” piāo le), a term popularized by MC Cai Fuqiang in his viral cover of the song “Don’t Float Too Much in Life (《做人不要太飘》).” A person might lament their own extravagance by saying, “I hailed a taxi to the supermarket. I must have been floating. (我竟然打车去超市，飘了。Wǒ jìngrán dǎchē qù chāoshì, piāo le.)” You can even pump up the phrase with more air-related metaphors. A critic may say of an arrogant B-list star: “He floats on his 15 minutes of fame, no need to even travel on airplanes anymore. (他有点儿名气就飘了，去哪儿都不用坐飞机了。Tā yǒu diǎnr míngqì jiù piāole, qù nǎr dōu bùyòng zuò fēijī le.)”

How to deal with an inflated ego that’s in danger of floating away from reality? As MC Cai warned, “If you dare to float, I’ll sharpen my knife. (你要敢飘，我就磨刀。 Nǐ yào gǎn piāo, wǒ jiù mó dāo.)” A short, sharp shock may bring these gasbags back to Earth temporarily, but, unfortunately, hot air will always rise.