The phrase "Kim Fatty the Third" has been censored on Chinese websites after furious North Korean officials said leader Kim Jong Un was being ridiculed.
The double-chinned despot is regularly insulted with the words "Jin San Pang" on Chinese search engine Baidu and blogging platform Weibo, but this week it returned no results.
The nickname pokes fun at the portly tyrant and his status as the third generation of the Kim family to rule the world's only hereditary communist dynasty.
China is North Korea's sole ally and props up the hermit kingdom but relations have deteriorated following the North's erratic nuclear weapons programme.
However, Beijing continues to support the Kim regime.
In particular, Chinese young people are dismissive of their country's reclusive partner and lampoon him on social media.
Chinese foreign ministry spokesman Geng Shuang said: "The Chinese government stays committed to building a healthy and civilised environment of opinions... We disapprove of referring to the leader of any country with insulting and mocking remarks."
He said reports of censorship did not "comply with facts".
"Kim Fatty the Third" is such a frequently searched term in China that it is sometimes suggested as an auto-complete on search engines.
Though "Jin San Pang" drew a blank this week, other versions of the nickname, such as "Kim Fat Fat Fat", remained untouched.