If you see this on your airplane boarding pass, prepare for a bad day

These four letters will have frequent flyers yelling four-letter words.

Deemed “the kiss of death” by jet-setters online, the “SSSS” stamp on a boarding pass is a sure-fire sign that a tripper’s flight plans could be severely delayed.

“It stands for ‘secondary security screening selection,’” Zach Griff, a senior aviation writer for virtual travel hub The Point Guys, based in New York, told Fox News. “It’s a measure implemented by security authorities in the US to screen certain passengers with additional checks.”

And while most sightseers would agree that skyway safety is key, many hate the hassle of being held up by TSA.

It’s an aggravating, yet necessary evil of air traveling.

Advancements in artificial intelligence have recently promised to make preflight scans as easy as ordering grub at a fast-food kiosk. However, most folks on the go still find themselves contending with long lines, baggage scans and intrusive searches at airport security checkpoints.

A few voluptuous vacationers even claim they’ve been wrongfully flagged by TSA technologies that have mistaken their huge hind parts for potentially dangerous cargo.

But for globetrotters with the dreaded “SSSS” on their tickets, there’s no blaming faulty robotics.

“Selectees for this enhanced security are chosen in the days leading up to a flight when airlines share the manifest with U.S. security authorities,” said Griff. “SSSS can also be entirely random, and there’s no way to know when booking your flight whether you’ll be chosen as SSSS.”

Travel influencers who’ve been hit with the annoying imprint say it’s like being locked in a “death trap.”

“If you ever get [SSSS] be prepared to be patted down four times over, harassed, made fun of in public and everything that comes with it,” warned a content creator, who was traveling between Canada and the US when his boarding pass was branded with the letters.

“Those extra inspection can take up to [30 minutes] more,” continued the avid adventurer, “so, obviously, that wouldn’t be nice.”

“Those four S’s are not your friend.”

Grumbles from disgruntled tourists notwithstanding, TSA representatives insist that a SSSS mark isn’t a curse. The airway watchmen claim, instead, that it’s a safety must.

“Security measures begin long before passengers arrive at the airport,” a spokesperson told Fox. “TSA works closely with the intelligence and law enforcement communities to share information.”

“Additional security measures are in place from the time passengers get to the airport until they arrive at their destination,” said the insider, adding that no traveler is able to bypass the SSSS search.

“In some cases, passengers are randomly selected for enhanced screening.”