unanswered

As adjectives the difference between unsolved and unanswered

is that unsolved is not yet solved while unanswered is that has not been answered or addressed.

As adjectives the difference between unanswerable and unanswered

is that unanswerable is not answerable; impossible to answer while unanswered is that has not been answered or addressed.

As a noun unanswerable

is something that cannot be answered.

As a noun mystery

is something secret or unexplainable; an unknown.

As an adjective unanswered is

that has not been answered or addressed.