President Donald Trump called Kim Jong Un “rocket man” earlier this week, and now the North Korean dictator has returned fire.

Kim gave Trump a nickname of his own ― and it’s one that sent Americans scrambling for a dictionary.

“I will surely and definitely tame the mentally deranged dotard with fire,” Kim said in a statement released by the North Korean government Thursday.

📈 Kim Jong Un calls Trump a mentally deranged U.S. dotard. Searches for 'dotard' are high as a kite. https://t.co/HztPoLSjXi — Merriam-Webster (@MerriamWebster) September 21, 2017

While the statement was full of choice words for Trump ― calling him “unfit,” “rogue” and “gangster” ― it was the word “dotard,” used twice, that seemed to catch everyone’s attention.

Freelance journalist Jihye Lee said the original statement in Korean used a term better translated as “old beast lunatic,” but it became “dotard” in the English version released by North Korea.

The statement caused the word “dotard” to trend on Twitter. Here are some of the reactions:

I don't even think there's a comeback after somebody calls you a #dotard — Gloria Fallon (@GloriaFallon123) September 22, 2017

How the fuck did I spend this much time on earth without having #dotard in my insult arsenal? Now I'm actually old enough to BE one. — Denis Leary (@denisleary) September 22, 2017

By making people look up the word #dotard, Kim Jong Un has done more for American education than Betsy DeVos. — The Incredible Sulk (@TurnUp_TheTweet) September 22, 2017

Rocket man & Dotard meet in nambia to avoid another bowling green massacre, Obama tapes the entire thing via microwave #dotard — rjb (@RobinJOJO) September 22, 2017

Trump will never escape the #dotard moniker now! Who would think that Kim Jong-Un would be the one to give him an effective nickname. — Roland Scahill (@rolandscahill) September 21, 2017

Dear American Journalists,



Shame on you for allowing Kim Jong Un to be the first person to call Donald a dotard.



Shame. On. You.#dotard. — Frederick Douglass (@HITEXECUTIVE) September 21, 2017

Whoa. It takes a strange kind of genius to pick a word that makes everybody find a dictionary and go "Holy cow, he IS a #dotard." — Amy Hunt ⛺️ (@amyhuntindallas) September 21, 2017

I wonder if a #Dotard can get #cofveve in #Nambia.🤔



Asking for someone who may need to <ahem> "leave" the US soon.#TrumpRussia🇷🇺 — Dr. Dena Grayson (@DrDenaGrayson) September 22, 2017

I hate it when Kim Jong-Un is borderline right in his description of the American president #dotard https://t.co/8Qr4LSwmLs — Will Saetren (@WillSaetren) September 22, 2017

Is this a word I can use in scrabble?#bigly #dotard — Nayna (@River70) September 22, 2017