Story highlights Trump has previously said Sen. Bernie Sanders, Sen. Lindsey Graham and Glenn Beck are nut jobs

By definition, nut job means a "mentally unbalanced person"

Washington (CNN) "Nut job" seems to be one of President Donald Trump's favorite insults for his political foes.

The President -- who The New York Times reported Friday bragged to two Russian officials that firing "nut job" FBI Director James Comey eased "great pressure" on him in regard to the Russia probe -- has a history of slapping the label on people he disagrees with.

By definition, nut job means a "mentally unbalanced person," according to Merriam-Webster, which tweeted Friday lookups of the word spiked 173,750%.

"'Nutjob' is our number 2 lookup right now," the dictionary's Twitter account tweeted Friday, using one of the two spellings for the phrase.

📈'Nutjob' is our number 2 lookup right now. https://t.co/bpGxeCtpSr — Merriam-Webster (@MerriamWebster) May 19, 2017

"'Nutjob' is derived from the word 'nut' ("a crazy person") combined with the word 'job,'" Merriam-Webster wrote in a blog post on its website Friday . "Yes, that's really it."