Bitter apple is a term used to refer to a fruit that has a strong, sour taste. Synonyms for the term include sour apple, tart apple, or acidic apple, as well as crabapple or wild apple. These terms are used to describe an apple that has a sharp, tangy flavor, and is typically used in baking recipes, or as a flavoring in drinks or sauces. Other synonyms for bitter apple may include acidic, pungent, or sharp-tasting fruit, which can be used to describe a variety of different fruits that have a similar taste to the bitter apple. Regardless of the term used, these fruits add a unique, zesty flavor to any recipe and are a delicious addition to any meal.