enigma Synonyms

closed book mystery brain-teaser riddle conundrum secret riddled why twister teaser stumper stickler sticker quandary question stealthiness quodlibet self-contradiction rebus sphinx roun puzzlement thriller puzzles braintwister classified information secrets tough nut to crack skeleton in the cupboard unknown quantity question mark brainteaser puzzler whodunit koan Gordian knot jigsaw puzzle polysemy magic number mystique difficult question puzzle grabber equivocacy dubiousness double-entendre dilemma difficulty desideratum cryptogram