recondite
/rɪˈkɒndaɪt/adjective
- (of a subject or knowledge) little known; abstruse（学科, 知识）玄妙的; 艰深的, 深奥的：
the book is full of recondite information.
书中充满深奥难懂的知识。
词源
mid 17th cent.: from Latin reconditus 'hidden, put away', past participle of recondere, from re- 'back' + condere 'put together, secrete'.