Etymology Learned borrowing from Ancient Greek ἐσωτερικός (esōterikós, “belonging to an inner circle”), from ἐσωτέρω (esōtérō, “further inside”), comparative of ἔσω (ésō, “within”), from ἐς (es), εἰς (eis, “into”) (the term esoteric referred originally to the secret teachings of Greek philosophers, versus public or exoteric ones).
1
Intended for or likely to be understood by only a small number of people with a specialized knowledge or interest, or an enlightened inner circle.
The writing in this manual is very esoteric; I’d need a degree in engineering just to understand it!
In this situation Hitler availed himself of a time-honored device-the use of esoteric language. In all periods of history, when government or society has put limits on public discussion, those who wish to circumvent censorship resort to the use of esoteric language. Exoterically understood, the text is unexceptionable, but to the insiders who know how to interpret the words, the message is revolutionary and dangerous to the status quo.1975, Lucy S. Dawidowicz, The War Against the Jews 1933-1945:
2
Having to do with concepts that are highly theoretical and without obvious practical application; often with mystical or religious connotations.
When he spoke to me of esoteric mysteries I wanted to say to him,"Don't give me that spiritual hokum, friend!"1976 September, Saul Bellow, Humboldt’s Gift, New York, N.Y.: Avon Books, →ISBN, page 278:
Etymology Learned borrowing from Ancient Greek ἐσωτερικός (esōterikós, “belonging to an inner circle”), from ἐσωτέρω (esōtérō, “further inside”), comparative of ἔσω (ésō, “within”), from ἐς (es), εἰς (eis, “into”) (the term esoteric referred originally to the secret teachings of Greek philosophers, versus public or exoteric ones).
1
An esoteric doctrine or treatise; esoteric philosophy.
2
One who believes, or is an initiate, in esoteric doctrines or rites.