Instead of a module, you can rely other offline/online sources like xml,json,api etc.
https://github.com/adambom/dictionary [json file]
http://dictionary-api.cambridge.org [REST api]
http://glosbe.com/a-api [REST api]
http://developer.oxforddictionaries.com/developer-resources/api-reference-guide/intro-using-the-oxford-dictionaries-api/ [REST api]
http://www.ibiblio.org/webster/ [XML, open source]