Word list sources

I have used WordNet from Princeton University for some projects. This is a lexical database in English. Global WordNet is an extension of the project trying to do the same for all languages.

You might also be interested in related projects at http://wordnet.princeton.edu/wordnet/related-projects/

This may not help at all, I don't know. But MediaWiki has an api for listing all pages belonging to a certain category. You could try using it on Wiktionary.org.

Notes:

• Each query only returns 500 results. However, at the end, it also specifies a parameter to use in another query to get the next 500 results.
• It includes everything in the specified category, even other sub-categories.
• Results seem to be in alphabetical order, though everything starting with a capital letter comes before anything in lower case.

Examples:

• First 500 page titles in the English Wiktionary in the cateogry "English nouns"
• Continuing, using the parameter specified at the end of the previous query
• First 500 page titles in the simple English Wiktionary in the category "Nouns"
• Again, continuing using the parameter specified at the end of the previous query

Hope this helps, it's what I could come up with.