You want to seem to know a subject matter without really studying it.
A website that publishes basic vocabularies of a growing number of subjects, so that you can talk about the subject and people would assume you know it. All this after reading and understanding the short list of words and definitions.
Have fun while learning and getting to know more about your language skills.
An app that gives you a sentence to rewrite. It then analyzes your sentence and gives you a score based on how developed your vocabulary is. It will also show you other possibilities for rewriting the sentence.