Colloquial abbreviation of Japanese, by 1880 as a noun, 1892 as an adjective, not originally pejorative but became so during World War II. It was protested by Japanese before the war, but did not begin to be taboo in the U.S. before 1960s. For some years after World War II in American English the word also functioned as a verb, "to execute a sneak attack upon," a reference to Pearl Harbor.
