ETYM Latin aenigma, Greek ainigma, from ainissesthai to speak darkly, from ainos tale, fable.
1. A dark, obscure, or inexplicable saying; a riddle; a statement, the hidden meaning of which is to be discovered or guessed.
2. An action, mode of action, or thing, which cannot be satisfactorily explained; a puzzle.

1. A story about a crime (usually murder) presented as a novel or play or movie; SYN. mystery story, whodunit.
2. Something that baffles understanding and cannot be explained; SYN. enigma, secret, closed book.

ETYM For opposal, in the sense of problem. Related to Oppose, Pose.
1. A particularly baffling problem; SYN. puzzler.
2. A toy that tests one's ingenuity.

Or conundrum; Verbal puzzle or question that offers clues rather than direct aids to solving it, and often involves unlikely comparisons. Riddles poems were common in Old English poetry.
In ancient literature, finding the answer to a riddle could be a matter of life and death. Oedipus, for example, became the ruler of the ancient Greek city of Thebes by solving the riddle of the Sphinx: “What goes on four legs in the morning, two in the afternoon, and three in the evening?” The answer is a human being—crawling on all fours as a baby, and walking with a stick in old age.
1. A coarse sieve (as for gravel).
2. A difficult problem; SYN. conundrum, enigma, brain-teaser. + prikaži više