It tasks you to find a path through random words by connecting them through their synonyms.
So, you're given a target word - let's say "morbid" - and then have to make your way to it from your starting word, which could be, well, anything - clown, enthusiastic, parachute... you get the idea.
This is all done by swiping through the pages of synonyms of the current word you're on. You then tap on the one you want to go on next, and so on.
The video below goes through the basics of how Synonymy works.
Yes, you heard that voice correctly - that is Richard Dawkings speaking; the God Delusion man himself. He's actually the narrator in Synonymy.
Another fact: Synonymy is made by a film director called Christopher Cinq-Mars Jarvis. Bit different, eh?
Synonymy supports multiplayer, and will have weekly challenges for you to try out in global competition.
It's due to arrive on iOS and Android on November 6th. There's more information on its website.