Developer Obo Games says its app Woffo has "more smarts than Crosswords, harder strategy than Scrabble and more twists than Boggle." Trust me, it's true.
Woffo is easily one of the more challenging word puzzlers that I've come across. Lately, I've been playing Scramble2 quite a bit, but Woffo has just displaced it. Thankfully, unlike Scramble2, there's no clock in Woffo to keep a wary eye on. Take all the time you need ( and you're going to need it) to fill in the blanks.