8 letters · 10 points in Scrabble
adjective confined to and understandable by only an enlightened inner circle
originLearned 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).
Etymology from Wiktionary, CC BY-SA 3.0