The phrase "are sweet on" is often used to describe romantic interest or infatuation with someone. However, there are many antonyms or words that express the opposite meaning of "are sweet on." These could include "are indifferent to," "dislike," "hate," or "detest." These words suggest a lack of romantic or emotional attachment towards someone, and instead describe a negative or hostile feeling. Other antonyms might include "are aloof from," "are cold towards," or "are unaware of," which implies a lack of interest or emotional investment towards a person. While "are sweet on" is often considered a positive phrase, these antonyms provide a useful range of words to describe a variety of emotional states and attitudes.