Webster’s Revised Unabridged Dictionary · 1913
Conundrum
Co·nun′drum (kō·nŭn′drŭm), n. [Origin unknown.] 1. A kind of riddle based upon some fanciful or fantastic resemblance between things quite unlike; a puzzling question, of which the answer is or involves a pun.
Or pun ambiguous, or conundrum quaint. J. Philips.
2. A question to which only a conjectural answer can be made.
Do you think life is long enough to let me speculate on conundrums like that? W. Black.