A new term has reappeared in the daily lexicon thanks to the North Korean leader Kim Jong-un, after he called President Donald Trump a "dotard".
A day earlier, Kim reacted to Trump's provocative speech at the U.N.by equating the US president to "a frightened dog" and a "mentally deranged USA dotard", employing an obscure insult for someone declining into senility.
To comply with a UN Security Council resolution calling for sanctions over North Korea's nuclear activity, China said Friday that it will limit its exports of refined petroleum products to Pyongyang as well as ban imports of the North's textiles.
The bellicose speech came after months of escalating tensions over advances in the rogue weapons programme operated by Pyongyang, which has defied tough sanctions to launch its sixth and largest nuclear test and to fire a series of missiles over Japan.
North Korea said on Friday it might test a hydrogen bomb over the Pacific Ocean after US President Donald Trump vowed to destroy the reclusive country, with leader Kim Jong Un promising to make a "mentally deranged" Trump pay dearly for his threats.
"With those words, President Trump handed the Kim regime the soundbite of the century", said Marcus Noland at the Peterson Institute for International Economics.
Pyongyang's response comes hours after Trump signed an executive order that aims to expand his authority to target people and institutions doing business with North Korea.
Joseph Cheng of the Chinese University of Hong Kong told Al Jazeera that "China wants to demonstrate its support of the world community's position dissuade North Korea from continuing to hold nuclear tests and long-range missile tests".
"The quake is presumed to have occurred naturally", an agency official said, according to South Korea's Yonhap news agency.
North Korea has been working on intercontinental ballistic missiles, which could reach USA shores.
Kim's statement was translated from Korean, of course, so it's possible that the word "dotard" doesn't quite capture what he meant to convey. "He was clearly offended by the speech, and what concerns me most is the response he says he is considering".
"This mission is a demonstration of USA resolve and a clear message that the President has many military options to defeat any threat", said Pentagon spokeswoman Dana White.
"This is unprecedented, as far as we can tell", Narang said.