In a post-pandemic world, office jargon is increasingly met with confusion and in some cases offense—with experts warning phrases like “boiling the ocean” just make communication more difficult.

It comes as a new report from LinkedIn and Duolingo identified not only the most confusing, but also the most overused, phrases in U.S. offices.

The study, which surveyed those age 18 through 76, also identified the phrases that are no longer acceptable in a professional environment.

And bad news if you’re a fan of “boiling the ocean” (meaning undertaking an impossible task): It was the phrase that a majority of respondents found most confusing.

Other baffling phrases included “herding cats” (a difficult task, particularly in terms of organization); “ducks in a row” (planning); “move the needle” (having an effect that people notice); and “run it up the flagpole” (testing the popularity of a proposal).

Also on the list of the top 10 most confusing phrases were “drinking the Kool-Aid” (demonstrating obedience); “out of pocket” (unavailable or unreachable); “building the plane while flying it” (engaging in a project before it’s thought out fully); “throwing spaghetti at the wall” (making a number of attempts to see what will be a success); and “juice worth the squeeze” (an effort justified by the outcome).

The problem with phrases like this? It actually makes it harder to communicate clearly between teams and geographies, said Chris Preston, founder of U.K.-based company culture experts The Culture Builders.

He outlined that there are three levels of jargon: global—phrases understood by those who speak a specific language; national—something only people of a certain nationality would understand; or local—something only people in a certain team or location would understand.

“Jargon creates an in-group and an out-group,” Preston said on a call with Fortune. “People often use these phrases because they think it sounds clever or have heard someone else say it, and thought they sounded clever.

“Often it’s aspirational, whereas if you actually listen to the best speakers and leaders they use stories and metaphors to get their point across, not jargon.”

Jargon damages productivity

Of the 8,000 working professionals across eight countries surveyed in the study, 57% said jargon wastes their time on multiple occasions every month.

The evidence also backs up Preston’s theory, with 49% of respondents saying that at least once a week a colleague uses a phrase which sounds like a foreign language.

“If I’m using loads of jargon and the person I’m speaking to doesn’t understand, that’s on me,” Preston said. “It’s not the listener’s job to try and interpret what you’re saying. You should be thinking about how to lift the level of engagement.”

With Gen Z entering the workforce in a more hybrid and online capacity, jargon can also perpetuate generational divides that aren’t really an issue until groups are being created.

Such tensions could come from jargon now considered outdated, with LinkedIn and Duolingo’s report highlighting a number of phrases which are no longer condoned in a corporate setting.

In the U.S. these include “bottom of the totem pole” (something that is unimportant); “blacklist” (to ban); or “the peanut gallery” (a source of insignificant criticism).

Duolingo’s senior learning and curriculum manager, Hope Wilson, told Fortune that when employees use phrases that are no longer accepted it can create “fracture in the shared corporate identity.”

She added: “The employees who use this jargon will feel an affinity for one another that others don’t share. And if the jargon is outright offensive, like some terms are, this fracture will be all the stronger.

“Unfortunately, these sorts of fractures are hard to address without conscious effort. People are generally quite bad at analyzing our own language use, and so the roots of these divisions can be hard to identify unless someone is explicitly analyzing and addressing the way language is used in the workplace.”

It makes you sound desperate

Jargon might not only waste your colleagues’ time but could also impact your professional goals, warned LinkedIn career expert Catherine Fisher.

“Being able to ‘talk the talk’ is an advantage for workers who get the jargon, but unfairly excludes and leaves behind those who aren’t as savvy with these terms,” she explained to Fortune. “You shouldn’t have to solve linguistic riddles just to get your work done and find growth opportunities.

“This disproportionately affects those who may not have English as their first language. Professionals from non–English-speaking households or backgrounds—including two-thirds of Latino workers (64%) and those fluent in English as a second language (67% FESL)—feel like they face a greater disadvantage when jargon is used.”

Wilson added that the use of jargon can “harm a person’s sense of belonging.”

She explained: “When you don’t understand what a colleague is saying, you feel embarrassed and sometimes even like an impostor—and it’s even worse when you’re the only person in a whole room who doesn’t understand what’s going on, and everyone else is nodding along.

“Additionally, it’s worth noting that heavy use of jargon isn’t a great thing even when you know the other people in the room understand what you’re saying. Jargon is a tool for projecting a workplace identity. So what does it say if every other word out of your mouth is a piece of jargon? It can make you sound desperate to belong.”