Discussion Forum—A Way with Words, a fun radio show and podcast about language

I have a list of words and I would like to be able to feed that list into something and get a return list of synonyms. I am working on a speech, and it's important to have a wide range of synonyms. The list is currently around 300 words, so typing them all into an online engine by hand individually is impractical. What I think I'd like to do is to then take the resulting list and do the same again, going about 2-3 levels deep, so I can then cull the words but have a great source of variety and ideas.

Any helpful suggestions would be appreciated.