In a New York Times Magazine interview published Wednesday, former Senate majority leader Harry Reid (D-Nevada) called Trump, “without question the worst president we’ve ever had.”

While these words might be familiar to many of president’s critics—a 2018 NYT opinion piece that surveyed 170 members of the American Political Science Association’s Presidents and Executive Politics section gave Trump the same moniker—Reid’s interview did introduce the masses to some new vocabulary.

“Trump is an interesting person, he is not immoral but is amoral,” Reid said, inspiring a 4,300% spike in looking up the word’s dictionary definition, according to Merriam-Webster.

📈'Amoral' is up 4300% today. It's defined as "having or showing no concern about whether behavior is morally right or wrong." https://t.co/3xWHqE4Jqy

— Merriam-Webster (@MerriamWebster) January 2, 2019

Reid, who retired from the Senate on New Year’s Day in 2017, continued with a definition of his own, telling the Times, “Amoral is when you shoot someone in the head, it doesn’t make a difference. No conscience.”

(On the 2016 campaign trail, Trump did famously tell supporters, “I could stand in the middle of 5th Avenue and shoot somebody and I wouldn’t lose voters.”)

While Merriam-Webster doesn’t give out raw data regarding how many people look up word definitions, associate editor and editorial ambassador Emily Brewster talked to Fortune about the 4,300% spike.

“It’s always interesting to us when a word spikes in lookups because a speaker or writer is calling attention to the word itself,” Brewster said in an email, noting, “Often a word will spike simply because it’s a relatively uncommon word that’s been used by someone with a large audience of readers or listeners.”

Brewster continued, “In this case, Reid was drawing attention to ‘amoral’ as it is distinguished from ‘immoral’—explicitly addressing a pair of words that offers a prime example of how replete the English language is with terms that cover the same basic territory while expressing distinct shades of meaning.”

According to the dictionary’s blog post on Reid’s statement, “A subtle distinction is made between the meanings of amoral and immoral that is connected with their classical prefixes: amoral denotes ‘without morals’ and immoral denotes ‘not moral’ or ‘against accepted morals,’ with the implication that, in the case of the latter term, expected standards are understood and breached, whereas, with amoral, expected standards of moral behavior are either unknown or unrecognized.”

Merriam-Webster’s twitter often takes a satiric approach to political rhetoric and, more recently, political typos. In December, the social media savvy account garnered attention for calling out Trump’s twitter typo that mistook a “smoking gun” for a “smocking gun.”

“Democrats can’t find a Smocking Gun tying the Trump campaign to Russia after James Comey’s testimony. No Smocking Gun…No Collusion.” @FoxNews That’s because there was NO COLLUSION. So now the Dems go to a simple private transaction, wrongly call it a campaign contribution,…

— Donald J. Trump (@realDonaldTrump) December 10, 2018

Today in Spellcheck Can't Save You:

'Smocking' is a type of embroidery made of many small folds sewn into place. https://t.co/3wbxPG24ne

— Merriam-Webster (@MerriamWebster) December 10, 2018

Merriam-Webster takes both “smocking” and “mocking” very seriously.