That cannot be told; indescribable, inexpressible, unspeakable.
Unclear, unintelligible, hard to get or explain the meaning of.
Neither reflecting nor emitting light.
Allowing little light to pass through, not translucent or transparent.
Obtuse, stupid.
Describes a type for which higher-level callers have no knowledge of data values or their representations; all operations are carried out by the type's defined abstract operators.
To make, render (more) opaque.
Something which is opaque rather than translucent.