Greetings--
You will find a free thesaurus at http://computers.net4free.org/moby (20 Mb download):
"Mobysaurus is a free, feature-rich English thesaurus and dictionary software that integrates Moby Thesaurus II, Roget's Thesaurus, GCIDE Dictionary and WordNet -- all royalty-free, powerful and most suitable for everyday reference. With this, you will feel it so much easier to choose the right word or words for every occasion or purpose."
Cheers
Robert