unriddle (unriddles, present participle unriddling; past and past participle unriddled)

1. (transitive) To figure out the answer#Noun|answer to (a riddle#Noun|riddle).
2. (transitive, by extension) To solve (a perplexing#Adjective|perplexing problem).
   • 1749, Henry Fielding, “In which More of the Talents of Mr. Benjamin will Appear, as well as Who this Extraordinary Person was”, in The History of Tom Jones, a Foundling. In Six Volumes, volume III, London: Printed by A[ndrew] Millar, […], OCLC 928184292 ↗, book VIII, page 186 ↗:

     'I your Enemy, Sir!' ſays he, with much Amazement, and ſome Sternneſs in his Look. 'Nay, be not angry,' ſaid Benjamin, 'for I promiſe you I am not. You are perfectly innocent of having intended me any Wrong; for you was then an Infant; but I ſhall, I believe, unriddle all this the Moment I mention my Name. Did you never hear, Sir, of one Partridge, who had the honour of being reputed your Father, and the Misfortune of being ruined by that Honour?'