riddle

A difficult problem.

A coarse sieve (as for gravel).

Spread or diffuse through.

“His campaign was riddled with accusations and personal attacks”

Separate with a riddle, as grain from chaff.

Explain a riddle.

Pierce with many holes.

“The bullets riddled his body”

Set a difficult problem or riddle.

“riddle me a riddle”

Speak in riddles.