Command over vocabulary means the use of the most appropriate and correct word, and not necessarily heavy words, for a given situation. Firstly, there are basic words, and then there are synonyms, which are advanced forms of the basic words, developed for particular situations and specific meanings. The more you are aware of synonyms and their correct usage, the more expressive your speech and composition becomes. Examples of basic words are good, bad, right, wrong, more, less, happy, sad, fast, slow, new, old, etc. Lets analyze the word bad. Following are its synonyms and the particular situation(s) where the word bad can be replaced with more appropriate words.
1. Naughty / mischievous - child
2. Base - (inferior) a cast, a thought
3. Awful - (very bad) work, performance
4. Corrupt dealings or activities involving bribery or obtaining money through unjust and unlawful means .