To pierce with numerous holes; perforate: riddle a target with bullets. To spread throughout: "Election campaigns have always been riddled with demagogy and worse\u201d ( New Republic). To put (gravel, for example) through a coarse sieve. A coarse sieve, as for gravel. A question or statement requiring thought to answer or understand; a conundrum. One that is perplexing; an enigma. To solve or explain. To propound or solve riddles. To speak in riddles.