mindmap root((神秘)) mystery applies to what cannot be fully understood by human reason or less strictly to whatever resists or defies explanation: the ~ of the stone monoliths on Easter Island. problem applies to any question or difficulty calling for a solution or causing concern: the ~s created by high technology. enigma applies to an utterance or behavior that is difficult to interpret: his suicide was an ~ his family never understood. riddle suggests an enigma or problem involving paradox or apparent contradiction: the ~ of the reclusive billionaire. puzzle applies to an enigma or problem involving paradox or apparent contradiction that challenges ingenuity for its solution: the mechanisms of heredity were long a ~ for scientists. conundrum applies to a riddle or puzzle whose answer involves a pun or less often to a problem whose solution can only be speculative: posed ~s to which there are no practical solutions.