Sweethearted is an adjective often used to describe someone who is affectionate, caring, and kind. However, not everyone possesses these qualities. One antonym for sweethearted is heartless, which describes someone who lacks empathy or compassion. Another antonym is cruel, which refers to someone who intentionally inflicts pain or suffering on others. Additionally, selfish and greedy individuals are not considered sweethearted since they prioritize their own interests over others. Lastly, cold and distant are opposites of sweethearted since they describe someone who is unwilling to connect emotionally with others. In conclusion, there are many antonyms for sweethearted, each of which reflects a different negative trait.