If you're a fan of word games and puzzles, Word Master is a great choice for your Android device. Developed by TopOfStack Apps, this free game is a good exercise for your vocabulary, challenging you to fill in the blank with the correct word.

The game is easy to play, but it gets harder as you progress through the levels. Each level presents you with a sentence with a missing word, and you have to choose the correct word from a list of options. You have a limited amount of time to choose the right word, so you have to think fast and act quickly. With over 500 levels, you'll have plenty of challenges to keep you entertained for hours.