If you use these 8 uncommon words in conversation, it’s a strong sign of high cognitive ability

I was reading in a café last week when I overheard two people talking at the next table.

One of them used the word “serendipity” to describe how they’d stumbled into their current job, and the other person looked genuinely confused. “What does that mean?” they asked.

There’s nothing wrong with not knowing a word. We all have gaps in our vocabulary.

But it got me thinking about something I’d noticed over the years.

The people I’ve worked with who could express themselves with precision, who had the right word for the exact situation, often seemed to be the ones who could untangle complex problems faster.

Turns out, there’s research backing this up. Laura Phillips, a neuropsychologist, points out that exposure to words is the single most important thing for building language pathways in the brain.

And those pathways don’t just help you sound clever at dinner parties. They help you think.

Using uncommon words isn’t about showing off.

It’s about having the tools to express nuance, to capture ideas that common words can’t quite reach.

When someone uses these words naturally in conversation, it often signals something deeper – a curiosity about language, a habit of reading, a mind that’s been exposed to more than just the everyday.

Here are eight uncommon words that, when used in conversation, suggest someone’s cognitive abilities are probably higher than average.

1) Esoteric

When someone uses “esoteric” in conversation, they’re describing knowledge that’s intended for or understood by only a small group of people.

It’s specialized, often obscure.

I first came across this word reading about my dad’s factory union meetings.

Some of the debates they had about organizing strategies were esoteric to anyone outside that world.

You had to understand the history, the context, the personalities involved.

People with high cognitive ability tend to recognize when they’re dealing with esoteric knowledge.

They don’t assume everyone knows what they know, and they don’t dismiss specialized information as irrelevant just because it’s niche.

Using this word shows you understand that not all knowledge is universal.

You’ve probably encountered enough different fields to notice when something requires insider understanding.

2) Paradigm

A paradigm is a framework or pattern of thinking. It’s the model through which you interpret information.

When I left corporate to start my consultancy, I had to shift my entire paradigm.

I’d been thinking like an employee, waiting for approval, following processes.

Running my own business meant thinking like someone who had to create the structure, not just operate within it.

People who use “paradigm” naturally tend to be systems thinkers.

They recognize that the way you frame a problem shapes the solutions you can see. They understand that different fields, different cultures, different generations operate under different paradigms.

This word signals metacognition, thinking about thinking. That’s a hallmark of cognitive sophistication.

3) Dichotomy

A dichotomy is a division into two opposing or contrasting parts.

It’s the recognition that something can be split into two distinct categories.

I’ve used this word a lot when trying to explain the political divides I see.

There’s often a false dichotomy presented – you’re either on one side or the other, with nothing in between.

People with sharper thinking recognize when a dichotomy is real and when it’s been artificially constructed.

Using this word suggests you’re comfortable with analytical thinking.

You can break down complex situations into their component parts and see where the real divisions lie versus where we’ve drawn artificial lines.

4) Nuance

Nuance is a subtle difference in meaning, expression, or response.

It’s what gets lost when conversations become polarized.

My sister, who’s a nurse, deals with nuance constantly. A patient’s symptoms might look straightforward on paper, but in reality, there are always small variations that matter.

The people who catch those details, the nuance – are usually the ones who get the diagnosis right.

When someone uses this word in conversation, they’re signaling that they don’t think in binaries.

They recognize that most situations contain layers, that context matters, that two things can be mostly similar but importantly different.

Research has shown that children from wealthier families are exposed to significantly more words by age three, which affects their ability to grasp these kinds of subtle distinctions later in life.

Nuance requires a rich vocabulary to express.

5) Superfluous

Something superfluous is unnecessary, excessive, or more than what’s needed.

I learned this one working in corporate. Every project seemed to generate superfluous documentation.

Reports that no one would read, meetings that could have been emails, processes that added steps without adding value.

People who use “superfluous” tend to be efficient thinkers.

They can identify what matters and what doesn’t. They’re not impressed by bulk or volume. They want substance.

This word shows you can evaluate necessity.

You don’t just accept things because they exist. You ask whether they serve a purpose.

6) Cogent

A cogent argument is clear, logical, and convincing. It holds together under scrutiny.

When I started writing seriously, I had to learn the difference between sounding smart and being cogent.

You can use impressive words and still make a weak argument.

Being cogent means your logic is sound, your evidence supports your claims, and someone reading carefully would find it hard to poke holes in what you’ve said.

People who use this word understand the difference between persuasive and correct.

They value arguments that stand up to examination, not just ones that sound good initially.

7) Zeitgeist

Zeitgeist is the defining spirit or mood of a particular period. It’s what’s in the air at a given moment in history.

I’ve found this word useful when trying to explain why certain ideas take hold when they do.

The zeitgeist of the late 2010s was different from now. The questions people were asking, the assumptions they were making, the things they cared about – all shifted.

Using “zeitgeist” suggests you think historically.

You recognize that we’re all shaped by our moment, and that moment is constantly changing.

This kind of temporal awareness is a marker of sophisticated thinking.

8) Ameliorate

To ameliorate something is to make it better, to improve a difficult situation.

During my divorce, a friend told me that time wouldn’t fix things, but it would ameliorate them.

The pain wouldn’t disappear, but it would become more manageable. That distinction mattered.

People who use “ameliorate” understand that improvement doesn’t always mean resolution.

Sometimes you can’t solve a problem, but you can make it less severe.

That’s a realistic, mature way of looking at challenges.

This word signals that someone thinks in degrees rather than absolutes.

They recognize that progress often comes in increments.

Conclusion

Language is a window into how someone thinks.

The words we use reflect the distinctions we can make, the concepts we’ve encountered, the mental models we’ve built.

None of these words makes someone smarter on their own.

But using them naturally suggests a person has been exposed to ideas beyond everyday conversation.

Research even shows that people who read regularly live almost two years longer on average, which tells you something about the value of engaging with language and ideas throughout your life.

The next time you’re in conversation and someone reaches for one of these words, pay attention.

There’s a good chance you’re talking to someone whose mind has been well-fed.