A friend insists that the phrase is a racist one, since it refers, or at one time referred, derogatorily to black people. Wanting to avoid both bigotry and political correctness, I asked the fine lexicographers at Merriam-Webster two questions:
1. Is this true?
2. If so, does Merriam-Webster's research show evidence that the phrase still carries racist meaning?
Associate Editor, Neil Serven, replied as follows:
While some construe the phrase “to call a spade a spade” to have racial allusions, its history suggests that no such allusion exists.
According to The Oxford English Dictionary, the phrase ultimately traces back to a Greek expression appearing in Plutarch's Apophthegmata. Plutarch's phrase contained a noun meaning "trough, basin, bowl, boat," which, it seems, was later mistranslated by Erasmus, who mistook the word for a derivative of a Greek term meaning "to dig." The error was carried over into English, where the phrase came to be rendered as “to call a spade a spade”; the first citation of the phrase listed in the OED dates from 1542.
The earliest usage of “spade” to refer to a black person in English dates from 1928. Most etymologists agree that this usage stems from the comparison of such a person’s skin color to the black markings found on playing cards.
The spade referenced in “to call a spade a spade,” then, is clearly of the digging implement sort, and has nothing to do with the offensive racial epithet.
Of course, if "some" people construe the phrase to be racist, and there is evidence for this (as Neil's response seems to suggest), then why do you judge the phrase to be completely benign, I asked? How much evidence does Merriam-Webster require to conclude that a phrase carries racial baggage? Indeed, isn't one of Merriam-Webster's axioms that definitions change with usage?
Some folks may interpret the phrase to be racist only due to their not knowing which sense of “spade” it originally referenced. We do not have any valid evidence of anyone using the phrase with deliberate racial allusion, and its contemporary meanings—“to call a thing by its right name however coarse” and “to speak frankly”—make no racial allusion.
However, Google shows a number of instances of people uncertain about whether the phrase should be considered offensive. This would suggest to me that there are a significant number of English speakers who choose to tread carefully with it despite its innocuous meaning and history. This kind of information, while interesting, really only pertains to the circumstances surrounding the phrase, and not to the meaning of the phrase itself, and so it wouldn’t factor into how a lexicographer would define the phrase.