I always cringe when I stumble across accusations of ethnic self-hated, which generally consist of the accuser taking the acusee's words completely out of context and twisting them beyond recognition.
But what if a word hated itself? Now that would be fascinating!
Well, the word "snob" takes being an auto-antonym to a seemingly impossible extreme. While your traditional auto-antonym simply contradicts itself (by containing multitudes, Walt Whitman-style), the word snob loathes its origins more heartily than even a guilt-ridden reformed snob might.
You see, my Compact O.E.D. doesn't list the current use of snob until definition 3d:
One who despises those who are considered inferior in rank, attainment, or taste.
Now, if for some unimaginable reason you were compelled to write in the distinctive style of dictionary definitions, how might you describe the object of a snob's scorn? As "a person belonging to the ordinary or lower classes of society"? As "one who has little or no breeding or good taste"?
That's precisely what I thought you'd say! And, believe it or not, those are snob's definitions 3a and 3b, respectively. Poor snob—trapped in the dictionary, one of its definitions hating two others. But how did this happen?
Well, the O.E.D. provides seemingly unrelated entries for definitions 1a ("a shoemaker or cobbler") and 1b ("the last sheep to be sheared"), but definition 2 holds some potential relevance for the self-loathing plight of snob: Apparently the word was used around the campus of Cambridge from 1796 to at least 1865 to describe (scornfully, of course), townspeople who were not studying at the university.
Thus, the "ordinary" person that definition 3a contrasts with ranked gentry could have been a synechdochal evolution of the contrast between the Cambridge locals and its supercillious students. But there's no verifying this theory, especially in light of the following:
A) The distinct possibility that the lower-class definition of snob came from an abbreviation of the Latin sine nobilitate, as AskOxford's linguistic faqs explain.
B) The implied etymology of the O.E.D.'s first citation for the ordinary-person definition of snob: In July 1831, the Lincoln Herald wrote, "The nobs have lost their dirty seats—the honest snobs have got 'em." Indeed, "nob" has a slang entry as "a person of some wealth or social distinction," and the transition from nob to its antonym snob is almost too simple.
The transition from snob meaning "commoner" to snob meaning "one who hates commoners," however, is somewhat more subtle. In 1848 Willian Thackeray popularized the word snob with The Book of Snobs, which classifies a snob as "he who meanly admires mean things."
How Thackeray came to this definition is a mystery to me, but he clearly specifies that it's "a great mistake to [...] think [Snobs] exist among the lower classes merely." According to Thackeray, "A great per-centage of Snobs [...] is to be found in every rank of this mortal life" (page 3).
So there you have it. The word snob hates itself, and owes it all to Thackeray, who quite perfectly calls himself one repeatedly throughout the book that started all this etymologic self-loathing.