"to call a spade a spade"

     [This is a fast-access FAQ excerpt.]
is NOT an ethnic slur.
   It derives from an ancient Greek expression:  ta syka syka, te:n
skaphe:n de skaphe:n onomasein = "to call a fig a fig, a trough a
trough".  This is first recorded in Aristophanes' play The Clouds
(423 B.C.), was used by Menander and Plutarch, and is still current
in modern Greek.  There has been a slight shift in meaning:  in
ancient times the phrase was often used pejoratively, to denote a
rude person who spoke his mind tactlessly; but it now, like the
English phrase, has an exclusively positive connotation.  It is
possible that both the fig and the trough were originally sexual
symbols.
   In the Renaissance, Erasmus confused Plutarch's "trough"
(skaphe:) with the Greek word for "digging tool" (skapheion;
the two words are etymologically connected, a trough being
something that is hollowed out) and rendered it in Latin as ligo.
Thence it was translated into English in 1542 by Nicholas Udall in
his translation of Erasmus's version as "to call a spade [...] a
spade".  (Bartlett's Familiar Quotations perpetuates Erasmus'
error by mistranslating skaphe: as "spade" three times under
Menander.)
   "To call a spade a bloody shovel" is not recorded until 1919.
"Spade" in the sense of "Negro" is not recorded until 1928.  (It
comes from the colour of the playing card symbol, via the phrase
"black as the ace of spades".)
   This, of course, does *not* necessarily render the modern use of
"to call a spade a spade" "politically correct".  Rosalie Maggio, in
The Bias-Free Word-Finder, writes:  "The expression is associated
with a racial slur and is to be avoided", and recommends using "to
speak plainly" or other alternatives instead.  In another entry, she
writes:  "Although by definition and derivation 'niggardly' and
'nigger' are completely unrelated, 'niggardly' is too close for
comfort to a word with profoundly negative associations.  Use
instead one of the many available alternatives:  stingy, miserly,
parsimonious..."  Beard and Cerf, in The Official Politically
Correct Handbook, p. 123, report that an administrator at the
University of California at Santa Cruz campaigned for the banning
of such phrases as "a chink in his armor" and "a nip in the air",
because "chink" and "nip" are also derogatory terms for "Chinese
person" and "Japanese person" respectively.  In the late 1970s in
the U.S., a boycott of the (now defunct) Sambo's restaurant chain
was organized, even though the name "Sambo's" was a combination of
the names of its two founders and did not come from the offensive
word for dark-skinned person.