North Korean leader Kim Jong-un responded to Trump’s fiery speech at the UN with one of his own, threatening to “tame the mentally deranged US dotard with fire.” But it was his use of the word “dotard” that caught America’s attention.

On Tuesday, President Donald Trump addressed the United Nations General Assembly for the first time. In his controversial speech, Trump referred to North Korean leader Kim Jong-un as “rocket man,” and threatened to “totally destroy” North Korea if the US was forced to defend itself.

In response, Kim issued a statement Thursday, calling Trump’s speech “unprecedented rude nonsense” and advising him to “exercise prudence in selecting words.”

Kim Jong Un fires back at Trump: "I will surely and definitely tame the mentally deranged U.S. dotard with fire." (via KCNA) pic.twitter.com/wZVdg5Q5Iq — Jon Passantino (@passantino) September 21, 2017

Kim stated that he would not abandon Pyongyang’s nuclear tests, and threatened to make Trump “pay dearly” for his speech.

“His remarks...have convinced me, rather than frightening or stopping me, that the path I chose is correct and that it is the one I have to follow to the last,” the statement read. “Action is the best option in treating the dotard who, hard of hearing, is uttering only what he wants to say.”

While his rhetoric offered nothing new of substance, Kim did introduce a lot of people to a new word, referring to Trump as a “dotard” multiple times.

The unfamiliar phrase caused many Americans to grab a dictionary. Merriam-Webster said online searches for the phrase were “high as a kite.”

📈 The word meant "imbecile" when it was first used in the 14th century. https://t.co/jqrHao0R9i — Merriam-Webster (@MerriamWebster) September 21, 2017

I've learned a new word today, and it's from Kim Jong-un, of all people. #dotard — Jerry Cupat (@JerryCupat) September 22, 2017

The Oxford dictionary defines “dotard” as: “An old person, especially one who has become weak or senile.”

I honestly, actually, had to look it up : #dotardpic.twitter.com/3JTnOpJv1C — Fin Gomez (@finnygo) September 21, 2017

Many were quick to praise Kim for his use of the uncommon English word, while some cemented it as a new nickname for Trump.

While I'm certain no one wins in a nuclear war, I might put my money on Kim Jong Un in a game of Scrabble vs Donald Trump. #dotard — Clever Thing Later (@CleverLater) September 21, 2017

Rocket Man vs Dotard Man — Kelsey D. Atherton (@AthertonKD) September 21, 2017

However, some pointed to the fact that Kim’s original statement in Korean referred to Trump with a phrase that directly translates to “lunatic old man.”

The English version of Kim Jong Un's fiery statement calls Trump "dotard." The Korean version says "늙다리미치광이" = lunatic old man pic.twitter.com/LNXWsJLtBB — Anna Fifield (@annafifield) September 21, 2017

BTW I had to look up the taunt ‘dotard.’ I’ve been inside #KCNA’s newsroom. They’re using very old Korean-English dictionaries. — Jean H. Lee (@newsjean) September 22, 2017

There were also many who criticized Americans for celebrating an oppressive dictator insulting the president.

Kim Jong Un rapes little girls, sells meth, and has killed thousands of his own people. Yet leftists are quoting him like a hero #dotardpic.twitter.com/RXTmUJD1qj — Marcus Hotep (@chrudat) September 22, 2017

Wow. Trump calls Kim Jung Un rocket man, and Kim calls Trump a mentally deranged dotard. Political leadership at its best. — Otis L. Sanford (@OtisSanford) September 21, 2017