brain-teaser Synonyms

enigma conundrum riddle unsolved problem sphinx secret roun riddled rebus question quandary puzzlement puzzle strait stumper Riddles question mark Chinese puzzle brainteaser closed book whodunit mystery story puzzler why twister teaser problem predicament poser difficulty crux confusion complication complexity charade bewilderment arcanum anagram abstrusity dilemma distraction doubt plight perplexity paradox mystification mystery maze labyrinth intricacy