The phrase "eat one's heart out" is typically used to express jealousy or sorrow over something that one cannot have or experience. There are many synonyms for this phrase that convey a similar sense of longing or sadness. Some examples include: yearn, pine, ache, sorrow, lament, and grieve. Other phrases that can be used interchangeably with "eat one's heart out" include: "waste away in envy," "feel a pang of longing," and "suffer from unrequited desire." These phrases can be used in a variety of contexts, such as romantic relationships, unfulfilled aspirations, or missed opportunities, and all express a sense of longing or sadness over what could have been.