JLPT Drill N5 Vocab helps you you master Japanese vocabulary, with a focus on terms likely to appear on the JLPT N5 test. What makes this app different is that it is constantly evaluating your mastery of each term, and auto-adjusting frequency of term appearance accordingly.
Although it takes the form of a test, answers are not graded and so you do not lose points for not knowing an answer. The "Dont know" button does not penalize you and pauses the timer so you can study a term as needed, so use it whenever you feel uncertain about a term.