Here are two Apps for Androids that feature crossword puzzles.
Each can be used to improve your English vocabulary and learn a new language words easily. They both feature free crosswords that you can do offline without an internet connection. Both are available on Google Play.
– Unlimited hints
– Easy levels for everyone
– Fun and educational
– Reveal letter hint
– Reveal word hint
– The size of the grid adjusts to your device
Crossword – Learn English Words: https://play.google.com/store/apps/details?id=com.orium.english.crosswords
English Crossword Puzzles: https://play.google.com/store/apps/details?id=com.appspot.orium_blog.crossword.eng