1. confined to and understandable by only an enlightened inner circle
a compilation of esoteric philosophical theories
2. Designed for, and understood by, the specially initiated alone; not communicated, or not intelligible, to the general body of followers; private; interior; acroamatic; -- said of the private and more recondite instructions and doctrines of philosophers. Opposed to exoteric.
3. Marked by secrecy or privacy; private; select; confidential; as, an esoteric purpose; an esoteric meeting.
4. An esoteric doctrine or treatise; esoteric philosophy; esoterics.