There are a multitude of synonyms for the term "overpurchased". This word typically refers to buying more of a product or item than what is needed or necessary. Some synonyms that could be used in its place include "overstocked", "oversupplied", "overbought", and "over-provisioned". Another way to phrase this idea could be to say that someone "stockpiled" or "hoarded" a particular item. These terms all convey a sense of excess and could be used in a variety of contexts, from describing someone's personal shopping habits to discussing inventory management for a business.