I am experimenting with word sense disambiguation using wordnet for my project. As a part of the project, I would like to convert a derived adjective or an adverb form to it's root noun form.

For example

beautiful ==> beauty wonderful ==> wonder

1. How can I achieve this? Is there any other dict other than wordnet that provides this kind of transformation?

2. It would be an added bonus for me if I can map the exact sense of the adjective word to its noun form with exact sense. Is that possible?

Thank you

Search google or SO for terms like 'stemming' and 'lemmatization', these terms might help you get what you are looking for.
For example, go to http://qaa.ath.cx/porter_js_demo.html and enter the words 'beautiful' and 'beauty', and you will see they both stem to the same token.
Porter stemmer essentially removes common suffixes found in the english language, so is by no means definitive, but is a pretty good place to start.
You can consider words that map to the same stem to be in some sense synonymous. If you can procure part of speech tags for all these words as well, you will be able to infer that beauty is the noun form of the adjective beautiful.