What’s the origin of “his name is mud”?

Dear Cecil: I am curious about a couple of expressions that seem to have their origins in the names of otherwise long-forgotten individuals. The first is “his name is mud (Mudd).” The second term, which is unknown to Americans but familiar to the British, is “pratt” (from Pratt, I guess), as in “he must have felt right pratt,” following some humiliating experience. Sue H., Chicago

Cecil replies:

I hate to be a party pooper, but there’s no great mystery to “pratt” (or, as it’s more commonly spelled, “prat”), and what mystery there is is impenetrable. It’s an old English slang expression that dates at least from the sixteenth century, translating roughly as “ass,” as in buttocks, not donkeys. As with most scatological slang, no one is quite sure where it come from. The word survives in American English in “pratfall”–that is, to fall on your prat.

As for “his name is mud,” there’s an old story that the expression derives from Dr. Samuel Mudd, who unwisely took pity on Abraham Lincoln’s assassin, John Wilkes Booth. Mudd treated the broken ankle Booth suffered in his leap to the stage of Ford’s Theater; for his trouble, he was sentenced to life in a federal prison. But Mudd isn’t being commemmorated in “his name is mud.” The phrase first appeared in print in 1820, 45 years before Lincoln’s assassination. It probably originates in another obscure bit of English slang–“mud” was an eighteenth century equivalent of our “dope” or “dolt” and was used through the nineteenth century by union workers as a rough equivalent of “scab.”

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.