Wiktionary
unconfessable
a. That cannot be confessed.
Usage examples of "unconfessable".
Now Glory was tossing into his arms ladies of high position but with an unconfessable past, anxious for novelties although exceedingly mature.
Another labels with a number the invincible remedy for the most unconfessable of diseases, and the genital scourge continues afflicting the world.
Perhaps the Masters of the World knew how to interpret it as a geomantic design, perhaps in its metamorphoses they knew how to read their instructions, their unconfessable mandates.
Was this a man, or hidden deep within his rags was there an angel or a devil whose compressed lips guarded a terrible and unconfessable secret?