Welcome, boys and girls, to Tobin's "Roots of Racist Slang".

I decided to look up why we have certain phrases for ethnic groups, and my results were spotty, but interesting.

Italians are called wops and dagos. Dago isn't very interesting, it's a variant of Diego, which was a popular name among Italians and Spaniards. However, wop is fascinating. To quote the dictionary, "Italian dialectal guappo, thug, from Spanish guapo, handsome, dashing, braggart, bully, from French dialectal wape, rogue, from Latin vappa, flat wine, scoundrel." Not only is that an incredibly long chain of evolution, but it's funny that you can see where it evolves from. An english speaker, overhearing "guappo", just says wop. This leads us to ...

Blacks are called spades, coons, niggers, and several other phrases that I'll omit because they're literal enough to be obvious. Spade and coon I didn't have much luck with, spade is from a deck of cards, where spades are black, and there are lots of phrases like "black as the queen of spades". Coon there is very little data on (at least in the dictionary I looked at), I would hypothesize that it's just that raccoons are brown and have the unfortunate tendency to dig in the trash, and other behaviors that humans also do, but it's pretty weak. Nigger is the easiest and clearest, it's "Alteration of dialectal neger, black person, from French nègre, from Spanish negro."

White terms are hard to track down. Whites are called crackers(white trash, usually) and honkeys, most commonly. Cracker has no obvious root, except that it apparently was a "noisy boister" in Shakespeare. Boring, and pretty much meaningless. Honkey is "Possibly blend of Wolof honq, red, pink, of light complexion, and hunky", where hunky is "a foreign born laborer, especially one of central European extraction". So it was apparently some sort of blue collar insult back in the day, but has evolved to mean all whites, and lost any sort of root significance. How disappointing.

The non-obvious asian slang terms are even more disappointing. Chink is theoretically just a variant of chinese. Gook is "Perhaps alteration of earlier goo-goo, native inhabitant of the Philippines, Pacific islander", which makes very little sense, and I'm not sure what the hell language goo-goo is supposed to come from.

I was going to look up some more, but the lack of good responses has me bored with this. The best slang by far was Italian, because it made sense, but I unfortunately did those first, so the rest of them were kind of a let down. Still interesting though.