there is excellent free encyclopedia, wikipedia.org - good tool to create this kind of thesaurus, with hyperlinked pages. Thousands of contributors. Do not reinvent the wheel.
No. Not really reinventing. wikipedia is a big, classic dictionary/encyclopedia. GrokSaurus is the reverse: It gives you a hint if you are completely, or at least somewhat, wrong. It helps you to find the proper word to ask wikipedia, or LinuxQuestions, or google, or even fellow human beings.