Margaret Collier read the blog “Do Crystallized Similes Give Animals a Bad Rap?” and came up with an interesting question about the title itself. Margaret writes, “I can understand what “bad rap” means—I think—but where did the phrase come from?”
A rap on the hand with a ruler or on the pants with a rod was a common punishment in schools and at home back in the 18th century when the word rap took on the meanings of “rebuke, reprimand”.
That sense of the word stuck and by the turn of the 20th century, rap had taken on the sense of a criminal charge or punishment. Taking the rap for burglary meant doing the time. By the 1940s criminal records were called rap sheets. This is how “a bad rap” or “bum rap” came to mean unfair criticism or punishment.
Why animals get such a bad rap in our metaphors remains a mystery.