Roget's Thesaurus: Entry 533 (Secret)

Make sure you have read the copyright information for this Project Gutenberg provided by, as well as the description -

#533. Secret.-- N. secret; dead secret, profound secret; arcanum[obs], mystery; latency &c 526; Asian mystery[obs]; sealed book, secrets of the prison house; le desous des cartes [Fr].

enigma, riddle, puzzle, nut to crack, conundrum, charade, rebus, logogriph[obs]; monogram, anagram; Sphinx; crux criticorum[Lat].

maze, labyrinth, Hyrcynian wood; intricacy, meander.

problem &c (question) 461; paradox &c (difficulty) 704; unintelligibility &c. 519; terra incognita &c. (ignorance) 491.

Adj. secret &c. (concealed) 528; involved &c, 248; labyrinthine, labyrinthian[obs], mazy.

confidential; top secret.