I found a used book yesterday: 2107 Curious Word Origins, Sayings and Expressions From White Elephants to Song and Dance, by Charles Earle Funk. That is quite a long title for a very thick book that contains interesting explanations of many oddities of the English language. From time to time, I will write about some of them.
“To pull the wool over one’s eyes” apparently originated in England several centuries ago. The expression means to fool or delude another. “Wool” is an allusion to a person’s hair, or perhaps a wig. If you pull the hair or the wig over someone’s eyes, that person will be temporarily blinded and easily fooled, perhaps originally by the wool-puller’s intention of robbing him or perhaps just as a tease.