as-yet-unknown

Adjective

 * 1) currently unknown
 * 2) * 1990, David Layzer Professor of Astrophysics Harvard University, Cosmogenesis : The Growth of Order in the Universe: The Growth of Order in ...
 * Now suppose that neutrons had some as-yet-unknown property that, if it could be observed, would enable us to predict their individual lifetimes.

Noun

 * 1) Something that is currently unknown.