undiscoverable

There was nothing else left to do; after that he would allow the enigma to drop into the abyss of undiscoverable things.

The one mind into which his thoughts had thus passed, remained ever mysteriously undiscoverable.

Poseidon and Aphrodite, Odin and Freya, vanish into the indefinite and undiscoverable at the approach of historical criticism.

It was a construction at whose center something undiscoverable had made a nest, with eggs in it.

It was strong only when the natural antecedents were not discovered, strongest when they could be declared undiscoverable.