The noun riddle has 2 senses (first 1 from tagged texts)
1. (1) riddle, conundrum, enigma, brain-teaser -- (a difficult problem)
2. riddle -- (a coarse sieve (as for gravel))
Overview of verb riddle
The verb riddle has 6 senses (first 2 from tagged texts)
1. (2) riddle -- (pierce with many holes; "The bullets riddled his body")
2. (1) riddle -- (set a difficult problem or riddle; "riddle me a riddle")
3. riddle, screen -- (separate with a riddle, as grain from chaff)
4. permeate, pervade, penetrate, interpenetrate, diffuse, imbue, riddle -- (spread or diffuse through; "An atmosphere of distrust has permeated this administration"; "music penetrated the entire building"; "His campaign was riddled with accusations and personal attacks")