When it comes to antonyms for "un-sweetened," there are a variety of options to choose from depending on the context. In terms of beverages and food, "sweetened" is the obvious antonym, referring to products that have been infused with sugar, honey, or other artificial sweeteners to create a sugary taste. However, in the case of personality traits or emotions, antonyms could include words like "pleasant," "delightful," or "enjoyable," all of which indicate a positive experience or disposition. Other antonyms for "un-sweetened" might include "flavored," "syrupy," or "candied," all of which suggest a more intense sweetness than would be present in an "un-sweetened" alternative.