'riddler' originates from English, specifically formed from the noun 'riddle' plus the agent suffix '-er'. The noun 'riddle' ultimately comes from Old English 'rædels', where the root 'rǣdan' meant 'to advise, interpret, or explain'.

'riddle' developed from Old English 'rædels' through Middle English forms such as 'redel' or 'riddle' and eventually became the modern English 'riddle'; the agentive form 'riddler' was created by adding '-er' to denote 'one who rids/asks riddles'.

Initially 'riddle' related to a saying or something to be interpreted (and the act of interpreting); over time its sense shifted toward a puzzling question, and 'riddler' came to mean 'one who poses riddles' or, figuratively, an enigmatic person.