This word is the single biggest tipoff that Trump is lying
President Donald Trump (Screen cap).

President Donald Trump exhibits a verbal tic that gives away some of his biggest whoppers.

The president tells demonstrable lies on a daily basis, but it's a "flashing red light" that he's lying when he recounts someone calling him "sir," according to CNN fact-checker Daniel Dale.

"Trump has told false 'sir' stories on all manner of subjects: health care, the Middle East, the courts, unions and -- just last week -- both tariffs and social media," Dale wrote. "But no genre of Trump story is more reliably sir-heavy than his collection of suspiciously similar tales about macho men breaking into tears of gratitude in his presence."

Trump claimed he called off a military strike on Iran last month after a general told him about the expected casualties, but Dale said he was certain the president was lying about something when he included his giveaway "tell" in the recollection.

"We were cocked & loaded to retaliate last night on 3 different sights when I asked, how many will die," Trump tweeted. "150 people, sir, was the answer from a General. 10 minutes before the strike I stopped it."

Earlier this year, Trump described farmers and ranchers standing behind him in 2017 as he signed an executive order ending a water regulation, and he claimed half of them were crying.

"'Sir, you gave me back my life,'" Trump recalled one particularly masculine man saying. "'You gave me back my property.'"

However, that signing ceremony was recorded on video, which is still available on the White House YouTube channel, and doesn't show anyone crying behind the president.

"I've been writing about Trump's 'sir' fabrications for a year now," Dale wrote. "As the Twitter mockery of these stories has increased, Trump has not slowed down one bit. He regaled audiences with tales about supposed 'sir' moments on consecutive days last week."

Trump told a gathering of supportive social media personalities that other supporters have been prevented from following him on Twitter, but the company won't allow them.

"'Sir, we want to follow you,'" Trump claimed they say. "'They don't let us on.'"

Dale said his suspicions about Iran, which were raised by Trump's "sir," were proven right after CNN reported the president had been told about the casualty estimate well in advance of the strike.