This app was mentioned in 3 comments, with an average of 1.33 upvotes
I found Anymemo to be very useful. There is an Android app for it. It's essentially flash cards, but it doesn't just show you all of them one after the other, it shows you those you have a harder time remembering more often than those you do well at.
As for context: Don't just add the source word and the target word, but include the context either in the question or as part of the answer and you're all set. It worked very well for me - I just did my words every morning on my commute on public transport. :)
Ankiも良かったけど
AnyMemoも良かった
https://play.google.com/store/apps/details?id=org.liberty.android.fantastischmemo