What words or expressions do you use every day that most reasonably well educated people wouldn't know?

If this were 1961, I’d be using strobogrammatic with an annoying frequency. ;)

I use “dreich” quite a lot which means wet dull and gloomy.

I’ve used “cool as a moose” since I was a kid. Probably learned it from my grandparents. My dad knew it too, but over the years I’ve met maybe 1–2 other people who ever heard of it, much less use it regularly, like me.

One time I said it aloud and some random person walking by finished with, “and twice as hairy”, which is the second part of the phrase.

I was so impressed.

When discussing numbers, I often use “order of magnitude”. A lot of people don’t get what I am saying.

When asked howare you, I’ll answer “Simply Elegant”.

Apparently, I’m the only person who remembers what “mortified” actually means. Hint: it’s not a synonym for “terrified”

Also, in my line of work, I retard things, which makes them retarded.

I often say that a store or restaurant that is very popular is doing “a land office business” which is obsolete, and refers to expansion of landownership in the American West in the 19th century. I have been saying it for over half a century, and I’m sure it started as a pretentious affectation that simply became habit.

I use, “you won’t melt” when people complain unreasonably about getting wet. It is a reference from the Wizard of Oz, and I would think you don’t need to be very educated to know the reference, but you do need to be familiar with the movie. My husband has never seen the movie.

I use a reference to Ray Bradbury short stories when it rains for days all day. All Summer in a Day, or looking for the sun dome, or I just say I feel stuck in a Ray Bradbury short story. All Summer in a Day is often shown as a movie to elementary school kids, so you definitely don’t need to be college educated for that either.

Don’t spit in the air. Meaning don’t judge others or say bad things about others, because it will come back and hit you in the face. Or, also a way of saying what comes around goes around. It is different than the expression spitting in the wind, which means a waste of time. I never use the latter.

Also, I use “wide breadth” a retail term for a large product assortment.
Another is “vertically integrated” when a company owns many parts of the business process, like owning the manufacturing, distributors, and retailers. Or, owning the farms, processing plants, and jobbers.

Some words:
Acquiesce
Antithesis
Commensurate
Jargon

My husband uses a shit ton of business idioms and business jargon, and I think it is too much and annoying and risks failing to communicate well. The two I can think of right now are “don’t move my cheese” and “don’t go down the rabbit hole” but there are so many more. He also adds in Southern sayings that he learned from his favorite boss.

@Smashley I use mortified, although not regularly. I used to use retard for something slowing down, but now that word is frowned upon for describing a person’s intellect, so I stopped using it all around. I assume musicians still use it.

Please, thank you, and your welcome.

@Tropical_Willie I used that line today after I read your take on it They spit water out their mouth in laughter.

@JLeslie – it’s offensive to use as a pejorative, but it’s the correct word for dealing with overactive dough.

@Smashley I understand your point, but probably I would only use it among people in the industry if at all. Retard can be used appropriately for many things not just slowing the rise of bread dough. The problem is a lot of people are ignorant about that word I think. Just like so many people are ignorant about the word ignorant that we have to be careful about calling anyone ignorant, because they think we are calling them stupid. I learned that during the Trump years. Pretty ironic when someone is arguing that ignorant means the same as stupid. Some people use it as synonymous I guess.

I guess we just have to know our audience. Probably, the more educated the more likely we can use retard and ignorant and be understood, or working in the particular industry as I mentioned in my first sentence.

Seeing as how at least half of these answers don’t fit my understanding of the question, I abstain.

@JLeslie – the emphasis falls differently when talking about dough, so I find people don’t tend to misunderstand me, though I rarely have use for it outside of work.

I just concocted one that I’ll strive to use henceforth- “tougher than a tardigrade”.

^^ Henceforth! There’s one!