riddle

Noun

• a coarse sieve (as for gravel)

• a difficult problem

Verb

• explain a riddle

• speak in riddles

• 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
    

• separate with a riddle, as grain from chaff

• set a difficult problem or riddle
  • riddle me a riddle
    

• pierce with many holes
  • The bullets riddled his body
    

Related words

• Synonyms: 
  conundrum , enigma , brain-teaser , permeate , pervade , penetrate , interpenetrate , diffuse , imbue , screen