It acts much like a thesaurus, except that it allows you to search with a definition, rather than with a single word. The definitions come from the famous open source database WordNet, so many thanks to the many contributors for creating such an impressive free resource. Although the word has a negative connotation, emulant is a word with the right vigour to describe a person who always seeks self-improvement. This project is more like a thesaurus in the sense that it returns synonyms for a query of words (or short phrases), but it also returns many generally related words that are not included in the thesauruses.
I created this tool after working on Related Words, which is a very similar tool, except that it uses a bunch of algorithms and several databases to find similar words in a search query. If not, you might want to take a look at Related Words, another project of mine that uses a different technique (although it doesn't work better with individual words, not with phrases). For this reason, this project, Reverse Dictionary, is designed to go hand in hand with Related Words to act as a set of tools to search for words and generate ideas.