unriddleable
adj/ʌnˈɹɪdələbəl/ · /ʌnˈɹɪdləbəl/
Etymology From un- + riddle + -able.
1
Unable to be solved or explained.
- 6 December, 1647, John Evelyn, letter to Sir Richard Browne O Heavens! we are now more in the dark than ever, and I protest unto you things were never more unriddleable than at this instant of time, after so many fair and promising expectations.