Note: I was unable to try this app out myself, so the below comes only from developer info, the app's page and other online sources.
What I never considered, though, was searching for TOEFL apps! TOEFL - the Test of English as a Foreign Language - interestingly includes a whole slew of words that lots of us who speak English as a primary language don't even know!
For those who aren't big fans of learning new vocabulary, and for those of you who want to read about the app and not my own life experiences, TOEFL Test - iBT Practice is an awesome app! Instead of simply using virtual flash cards or reading a list of words and their definitions, you also get games to play in addition to the quizzes, flash cards, charts and so on, perfect for people who learn all sorts of ways!
The free version includes all of the features of the full "pro" version but with fewer words (150 instead of 3000!!!), so you can easily see what the full app has to offer for free! If you decide to go for the pro version (hint: you should!), it's only 99 cents anyway, far less than the cost of a boring book.
Available For: Android and iOS (Free version; Pro version $0.99)
Developed By: MediaAgility