Gaijin. It seems we hear the word every day. For some, it's merely harmless shorthand for "gaikokujin" (foreigner). Even Wikipedia (that online wall for intellectual graffiti artists) had a section on "political correctness" that claimed illiterate and oversensitive Westerners had misunderstood the Japanese word.
I take a different view: Gaijin is not merely a word; it is an epithet — about the billions of people who are not Japanese. It makes assumptions about them that go beyond nationality.
Let's deal with the basic counterarguments: Calling gaijin a mere contraction of gaikokujin is not historically accurate. According to ancient texts and prewar dictionaries, gaijin (or "guwaijin" in the contemporary rendering) once referred to Japanese people too. Anyone not from your village, in-group etc., was one. It was a way of showing you don't belong here — even (according to my 1978 Kojien, Japan's premier dictionary) "regarded as an enemy" ("tekishi"). Back then there were other (even more unsavory) words for foreigners anyway, so gaijin has a separate etymology from words specifically meaning "extra-national."