What´s an oxymoron again ? Who or what is quixotic ? You might find the Dictionary Tooltip Extension for Firefox useful if you happen to stumble upon words that you have never heard before (or know but have no definition at hand).
This extension lets you mark a work and shows a definition of that word after one of the following three possible actions. 1. You doubleclick the word, 2. You right-click and select view definition and 3. you hit the shortcut CTRL + SHIFT + D. A mighty useful extension not only for natives but also people with English as their second or even third language.

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