Bitter pignut is a term typically used in the southern United States to refer to a type of hickory tree. However, if you're looking for other ways to describe this nutty flavor, there are plenty of synonyms to choose from. Some may describe it as acrid, sharp, and pungent, while others may use words like tart, tangy, or even astringent to describe the taste. The use of descriptors like these can be useful when describing flavors in cooking, as they can help convey the exact sensation one might expect when biting into a bitter pignut or other similar food item.