Convert Word to Semantic Prime Does anyone know of any libraries I could use to convert a word into a semantic prime, given a list of approved primes? 

In other words, given a sentence or a word, I would like to find the combination of "prime" words that best match the input semantically. 

A good example of this would be a function that takes in a Wikipedia article and outputs something like Simple Wikipedia - it has the same semantic content, but restricts word usage to a number of prime words (in this case, simpler words).

Another example: say my primes are ["person", "move", "tool", "nice", "building"].

Then I would like to have some function, library, or NLP algorithm that converts "hammer" into ["building", "tool"], "car" into ["moving", "tool"], and  "friend" into ["nice", "person"].

My first intuition was to use word2vec: loop through every combination of the primes and find the combination of primes who's vector most closely matches the original word. However, I suspect this will not work out very well (partially because vector addition doesn't seem to be accurate enough). Is there a more robust way to do this?
Finding a robust model for what you are looking or trying to build is quite difficult at this point of time and as per I know there are no any such existing algorithms to do this.

One approach that you can follow is make a Knowledge base for your primes containing info/word it can be related with.
To handle most of the relation you will need a word dictionary which contains all the possible related words. Making such an exhaustive dictionary is not completely possible/feasible. But if you have some domain specific work you can make a dictionary which can handle 80% of you cases. You can use wordnet/word2vec to find the most similar words of your base primes and can extrapolate those words.

Apart from these you would need a set of possible relations that the word can have. For this you can use models like Open IE to extract the Subject-Object-Relation and you can associate these relations with your primes. But for this you will require a dataset of your domain from which you can get the possible relations.