Word games has a large vocabulary included - well over 200,000 words! These are words selected from an even larger list in our database, but we have selected those which are small enough to fit into the game boards (maximum 13 letters), and are in reasonably common use - we selected the most used words to include. (The Scrabble List includes some words up to 15 letters long, and is approximately 180,000 words long, so hopefully we've included a wide enough dictionary!)
Each of the games includes a minimum word length - in all cases 2 letter words won't be accepted.
We've also worked hard to identify words which have an American English or British English spelling and mark those accordingly. There is an option in the settings to choose which of these dictionaries is appropriate for you!
There are also a number of words which (in our opinion) have the capability to cause offense. Each person has their own opinion on which words are bad, and this very much depends on upbringing and location, although there are a number of words which most people agree on being offensive. These words are actually included in the dictionary, but are flagged so that they are never given to the user as target words in Wordsearch or Spellmaster, but as they are still valid words, if you can construct them in the open games (and some people take a particular pleasure in doing so... you know who you are!), you'll get the points for them.
The Kid Safe option in the settings is on by default, which means that they will not be accepted even if they are constructed, but you can turn this off if you find it restrictive. We often get complaints that some of the words included in the offensive filter are not really that bad, and have a perfectly acceptably meaning too. We've taken a pragmatic approach on these, and tried to err on the side of being a bit too safe if we're not sure.
If you do find a word that you find offensive in the game, please be aware that we haven't included it deliberately to cause offense - the chances are we didn't realise! Please get in touch and let us know, and we'll include it as an exclusion in the next word list update.
Where we can we've included definitions for the words, and these have come from Wiktionary which is the online free dictionary by the same group who run Wikipedia. If you think a definition is incorrect, then go there and suggest edits - they're always after new contributors! We will import the updated definitions when we do an update so your correction will come to us that way :)