The best replacement for riddle is puzzle.

The best alternatives to riddle are rated as following:
★★★★★  puzzle
★★★★  joke
★★  simmler
★★  bugtong
★★  dan simmler
★★  enigma
★  clements
★  mills
★  pierson
★  harry potter
  rndj
  che mills
  maguire
  nick osipczak
  chris clements
  tony noun
  atp
  voldemort

Your alternative for riddle is not listed? Suggest!
Speaking about riddle, one probably shouldn't forget about two doors.

Other search terms related to riddle and their ratings are:
★★★★★ two doors
★ fox chicken and corn
light bulbs and switches
You have in mind a companion for riddle and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of riddle in all years. Click on graph for more.
riddle
puzzle
joke