The term "sick heart" refers to a feeling of emotional pain or sadness. There are several synonyms that can be used to describe this feeling, including heavy-hearted, despondent, dejected, crestfallen, and disheartened. These words all convey a sense of melancholy and despair that can be difficult to shake. Other synonyms for "sick heart" might include forlorn, mournful, woebegone, and sorrowful. These words all describe a deep sense of sadness that can be difficult to express in words. Whether you are experiencing a "sick heart" yourself or trying to understand someone who is, these synonyms can help you to better articulate the deep emotions that come with this feeling.