Vocabulary is an important part of being able to express yourself effectively. It’s a good idea to read unfamiliar material with a dictionary close by. That way, you can easily look up any words you don’t understand. But what if you aren’t allowed to use a dictionary? In those situations, which include just about all standardized tests, you need to be able to make a good guess about the meaning of a word based on its context. Here is what we mean:
Even though they give her nightmares, Joyce likes gruesome movies.
Let’s say you don’t know exactly what gruesome means. But the sentence tells you that gruesome movies give Joyce nightmares, so it’s a good bet that gruesome doesn’t mean "romantic" or "funny." What kind of movies would give someone nightmares? Just using context and your own common sense, you can figure out that gruesome means something close to "scary" or "violent."
Once you are out of a testing situation, you can refine your definition by looking up those unfamiliar words in the dictionary. But your context definitions will keep you from getting stuck during a test.