Old but GOOD (from 2010)
This Scrabble (188.8.131.52) doesn't work on Mac after Lion, but it's better than newer versions available in July 2016. The dictionary defines words and immediately shows red for unacceptable words, There are good animations for moving tiles. Play alone or pass and play. Offline!!! just for this game, I have a Lion virtual machine installed with Parallels on my Mac, Yosemite.