It sounds like you understand the vocabulary in context, but can't necessarily articulate a specific dictionary-style definition on demand. That's not too unusual; most of us can use at least some words that we can't define--and, of course, using and understanding them correctly is more important than defining them. Sometimes it helps when one encounters words in multiple contexts, each of which adds a bit of nuance to the meaning of the word. You can also try thinking about how you would explain the meaning of the sentence, with the word in context, to someone else. That might help you solidify how you articulate the meaning, so that it becomes a little bit more accessible in other contexts, or in isolation.
Your English curriculum is fairly typical of what high schools expect now. And reading numerous classic novels doesn't have to be a mark of arrogance, if you don't rub it in other people's faces! The novels are worth reading in their own right.
I would second Arthur C. Clarke. You may know that he was a legitimate scientific thinker (the Clarke geostationary orbit is named after him, as he was the first to posit its existence--in one of his novellas, no less). Isaac Asimov's literary merit is a bit less than Clarke's, but his scientific bona fides are equally strong (PhD in chemistry). Larry Niven's Ringworld series is also high-concept classic science fiction.
What else do you like to read?
