Here, let me help a few out including myself.
es·o·ter·ic (s-trk)
adj.
1.
a. Intended for or understood by only a particular group: an esoteric cult. See Synonyms at mysterious.
b. Of or relating to that which is known by a restricted number of people.
2.
a. Confined to a small group: esoteric interests.
b. Not publicly disclosed; confidential.