In a statement through a North Korean news agency Thursday, Kim Jong-un slammed Donald Trump's recent UN address, calling the president a "mentally deranged U.S. dotard."

So ... what does that mean?

If you've been wondering about the bizarre insult (pronounced DOE-turd, as in deer poop, BTW) you're not the only one. In fact, so many people were Googling the term that Merriam-Webster went ahead and tweeted the definition.

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According to the dictionary (thanks, dictionary!), a dotard is "a person in his or her dotage," which--classic dictionary move--is extremely unhelpful.

That's probably why the word dotageis also trending on Merriam-Webster.com: "a state or period of senile decay marked by decline of mental poise and alertness." It was first used during the 14th century, and is derived from the Middle English "doten," which means "to dote."

Damn!

So why choose this particular word? Well, it likely wasn't in the original statement, to be honest. Per Jean H. Lee, an Associated Press reporter who covers North Korea,the Korean Central News Agency, which published the statement, uses "very old Korean-English dictionaries" and thus might end up using--you guessed it--very old words.

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And according to a Friday report from the AP, "dotard" is likely a direct translation of the Korean word "neukdari," a disparaging way to refer to an elderly person. Sometimes, the word becomes more neutral in its English translation -- i.e. just "old person" -- but here, it seems to have retained its full derogatory power. Cool!

While the word is certainly old-school, it's definitely popped up in the media in recent years. In fact, just a few weeks ago, The Atlantic published a reader submission containing the word "dotage." In the past decade or so, it's been used to describe former New York Knicks executive Phil Jackson as well as Cheeta, a chimpanzee who is also an actor.

Before that, it appeared in works by literary greats like Shakespeare, Chaucer, Herman Melville, J.R.R. Tolkien, and Alfred, Lord Tennyson. ("'Curse him!' curse your fellow-victim? call him dotard in your rage? / Eyes that lured a doting boyhood well might fool a dotard's age," wrote Tennyson in "Locksley Hall, Sixty Years After.")

The term was also deployed in the political sphere. Donald Trump might be particularly annoyed to discover that it was once used to describe Andrew Jackson, one of his favorite fellow presidents. (The xenophobic apple doesn't fall far from the xenophobic tree, it seems.)

Still, if you want to use the word yourself, it's probably best to be quite cautious -- or at least, more cautious than Kim Jong-un and Donald Trump, which is a good goal.

At its core, "dotard" makes a judgement about a person's mental health, which is not a particularly wise thing to be doing to your peers as you dance through life. If you can't help yourself, we might suggest saying it to a movie character, or to your senior dog the next time it mistakes its own tail for a squirrel.

Also, it's best not to threaten nuclear war.