Synonyms For "Supersecret" :

2 syllables:

closed book, concealed, covert, hidden, inward, mystic, occult, orphic, private, privy

3 syllables:

arcanum, clandestine, enigma, mystery, mystical, secluded, unavowed, underground

4 syllables:

confidential, mysterious, surreptitious, unacknowledged, undercover