Looking for vocab apps (and webpages)

Are there any vocabulary apps or webpages where you can increase your advanced vocabulary with lists of words (including definitions) where you can save the words you like in one or more lists, to practice later? I have only found one called SAT flash cards, which is great, but I miss the option of saving the words in different lists (such as one for words you want to incorporate in your passive vocabulary, and one for words already in your passive vocabulary, that you want to include in your active vocabulary). I also miss the option of importing the words to a MS word file or similar. I´m quite particular with what words I consider worthwhile learning, so I tend to prefer to pic only a few of the ones I see repeatedly.