Esoteric

ˌɛsəˈtɛrɪk

adjective

intended for or likely to be understood by only a small number of people with a specialized knowledge or interest

The word 'esoteric' originates from the Greek word 'esoterikos,' meaning inner or within. It refers to knowledge that is understood or intended to be understood by only a small group of people with a specialized interest or knowledge in a particular field.

(with a smile) Your claim then is that your truth is of so esoteric a nature that it is beyond the understanding of a plain man.

Asimov, Isaac

Foundation 1 - Foundation

The exoteric and the esoteric, as they were formerly distinguished by philosophers—among the Indians, as among the Greeks, Persians, and Mussulmans, in short, wherever people believed in gradations of rank and not in equality and equal rights—are not so much in contradistinction to one another in respect to the exoteric class, standing without, and viewing, estimating, measuring, and judging from the outside, and not from the inside; the more essential distinction is that the class in question views things from below upwards—while the esoteric class views things from above downwards.

Friedrich Nietzsche

Beyond Good and Evil

To be intoxicated by a single glass of wine; I have experienced this pleasure when I have drunk the liquor of the esoteric doctrines.” I kept Homer’s Iliad on my table through the summer, though I looked at his page only now and then.

Henry David Thoreau

Walden

The life esoteric is not for ordinary person.

James Joyce

Ulysses

Late afternoon in the library, all of the esoteric machinery around him faded into a sensory background, and a ten-year-old sat silently before a scanner hugging the knowledge to himself.

Frank Herbert

Heretics of Dune

Yossarian was stunned at how waxen and ghastly Snowden’s bare leg looked, how loathsome, how lifeless and esoteric the downy, fine, curled blond hairs on his odd white shin and calf.

Heller, Joseph

Catch-22

Of any connection between Apollo and the Sun, whatever may have existed in the more esoteric doctrine of the Greek sanctuaries, there is no trace in either Iliad or Odyssey.

Homer

The Iliad