North Korean leader Kim Jong Un lashed out at President Donald Trump on Thursday — and sent many scrambling for their dictionaries.

“ ‘I will surely and definitely tame the mentally deranged U.S. dotard with fire.’ ”

So first, what’s a dotard? “A person, especially an old person, exhibiting a decline in mental faculties; a weak-minded or foolish old person,” according to Dictionary.com. The emphasis is on the first syllable, notes Merriam-Webster, as in the related word “dotage.”

It set off a flurry of honestly impressed reactions from Twitter:

Now that we have that out of the way ...

Kim issued a blistering statement through the official Korean Central News Agency and said he was thinking about how to respond to Trump’s latest moves, which include a speech at the United Nations on Tuesday in which he threatened to “totally destroy” North Korea and referred to Kim as “Rocket Man.” On Thursday, Trump ordered expanded sanctions against the rogue nation, targeting individuals or companies trading with the country.

“I will make the man holding the prerogative of the supreme command in the U.S. pay dearly for his speech,” Kim said Thursday.

To no one’s surprise, Kim was not a fan of the speech, saying Trump “made unprecedented rude nonsense one has never heard from any of his predecessors.”

“I’d like to advise Trump to exercise prudence in selecting words and to be considerate of whom he speaks to when making a speech in front of the world,” Kim said, later calling Trump “a gangster fond of playing with fire.”