Van Buren is a proper noun and its synonyms would not be related to the name itself. However, if we consider the meaning of the name, which is a Dutch surname derived from "van Buren" which means "from Buren" in Dutch, then some synonyms could be "Dutch surname", "ancestral name", or "family name". Another meaning could be that it refers to the eighth president of the United States, Martin Van Buren. In this case, some synonyms could be "president", "statesman", or "politician".