yellow

according to The American Heritage Book of English Usage, "Of the color terms used as racial labels, yellow, referring to Asians, is perhaps the least used and the most clearly offensive." Yellow has also been used to single out Jews: in some countries during the Holocaust, they were forced to wear a yellow badge; the Nazis required yellow stars. The color has also been associated with cowardice. See also high yellow, etc., yellow/yellow-bellied, Yellow Peril.