“She is an uncut diamond—I’ve said so several times.”
The she: Anastassya Filippovna Barashkov, more familiarly known as Nastassya, who is a deeply troubled and distressed young woman. The speaker: Afanassy Ivanovich Totsky, wealthy friend of Nastassya’s father and her ward following the death of her parents until she grew into a beautiful mature woman, at which point he made plans to make her his mistress. As to what this metaphor may actually mean—and it could cut either way—read the book.
“He is queerly dressed, like a German”
The specific job of a simile is to make a comparison that is universally recognized enough to create a kind of shorthand; the simile is one of the most effective tools available for cutting down word count. Compare something that is tricky to describe with something that is the opposite of tricky and a writer just saved himself a lot of trouble. But not all similes work this way because not comparisons being made are equal in their universality. For instance, the comparison to those of Germanic nationality as being particularly notable for their queer attention to style. If you get the comparison, then the connection clicks and you immediately get what the author was going for. If not, you may wind up even more confused.
“Beauty is a riddle.”
On the other hand, sometimes a metaphor gains from the universality of its ambiguity. Such is the case with an assertion such as this. No doubt, beauty is a riddle, but what kind of riddle and how funny the riddle may be is going to be different for each person. While a simile generally benefits from precision, a simple metaphor like this example of gains power from its very vagueness.
“It’s a good thing that he doesn’t stick at home and isn’t shy like a noodle.”
Another simile that could be somewhat perplexing. “Shy like a noodle” is not exactly a familiar term, though at least one could probably work it out more easily than figuring out what being German has to do with dressing queerly. Part of the joy of reading a writer like Dostoevsky is reveling in the creative ways he uses language. Perhaps noodles are well known for being shy in Russia, but for most readers this presents another opportunity to think about what the author is trying to suggest.
The End
Interestingly, The Idiot actually comes to a close on a metaphorical note. The particular object of the metaphor is a reference to a recurring theme throughout the novel; the idea that viewing life as fantasy is preferable to seeing the reality.
“And all this, all this life abroad, and this Europe of yours is all a fantasy, and all of us abroad are only a fantasy . . . remember my words, you’ll see it for yourself!” she concluded almost wrathfully, as she parted from Yevgeny Pavlovitch.”