Singapore's high court has fined the prime minister's nephew $10,884 (around AED 39,976) for scandalising the judiciary.
Li Shengwu's case involved a private Facebook post in 2017 in which he said the Singapore government was "very litigious and has a pliant court system".
His comments related to a battle over the home of Singapore's founding father, Lee Kuan Yew, which had put Li's father, Lee Hsien Yang, at loggerheads with current prime minister, Lee Hsien Loong.
Li, a 35-year-old assistant professor at Harvard University in the United States, had opted earlier not to participate in the proceedings against him and was not represented in court for Wednesday's judgement.
Justice Kannan Ramesh said in his decision that the allegation in the post "is without any basis" and "does not amount to fair criticism".
If Li does not pay the fine in two weeks, he will face one week in prison, according to a copy of the judgement.
"I disagree with the judgement," Li said in a Facebook post on Wednesday.
"In response to three words in a private Facebook post, the government has wasted three years of civil servants' time".