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v. Simple past tense and past participle of unriddle.

"It was there, that, about 1829, was committed that mysterious assassination, called “The assassination of the Fontainebleau barrier,” whose authors justice was never able to discover; a melancholy problem which has never been elucidated, a frightful enigma which has never been unriddled."

unriddled    unriddles    unriddling   

explain