riddle1
  
  n.
 a question or statement phrased so as to require ingenuity in ascertaining its answer or meaning. 
▸a person or thing that is difficult to understand.
v.
 archaic speak in or pose riddles. 
▸explain (a riddle) to.
 
  Derivative
  
  Etymology
  OE rædels, rædelse ‘opinion, conjecture, riddle’; rel. to read.
 
  
    
riddle2
  
  v.
  - make many holes in, especially with gunshot. 
▸fill or permeate with something undesirable:
 the law is riddled with loopholes.
 - pass through a riddle. 
▸remove ashes or other unwanted material from (a fire or stove) with a sieve.
 
n.
 a large coarse sieve, especially one for separating ashes from cinders or sand from gravel.
 
  Etymology
  OE hriddel, of Gmc origin.