What VR? What dictionary? What are the criteria for "limit the words to a best match"? Do you mean that if someone enters "prunella", you substitute "prune"?
I have a dictionary (an AI/NLP database of words used by English speakers) and code which looks for input words and if one is not in the dictionary, returns the closest match(es). This would normally be used as a spelling corrector. The code is not real simple and would not work with non-English languages.
If by "VR" mean like for a game and by "dictionary" you mean a limited number of words, then it's a pretty simple look-up.