'Riddler' originates from English, specifically formed from the word 'riddle' + the agentive suffix '-er', where 'riddle' originally signified 'a puzzling question' or 'conundrum'.

'Riddle' in Middle English came from two Old English sources: Old English 'rædels' (related to 'guess' or 'opinion') and Old English 'hriddel' (a sieve). These senses merged in Middle English into 'riddle' (puzzle, or a device that separates), and the agent noun 'riddler' developed later in modern English as 'riddle' + '-er'.

Initially associated with either the puzzle sense ('one who poses riddles') or the sieve/perforation sense ('one who makes holes'); over time the primary modern sense became 'one who poses riddles', and it also became established as a proper name for the Batman villain 'The Riddler'.