eat one's heart out

eat (one's) heart out

1. To feel great sadness. I feel just awful for Mary—she's been eating her heart out ever since she found out she was rejected by her top-choice school.
2. To be very jealous. In this usage, the phrase is often said as an imperative and sometimes mentions a famous person (when the speaker comically claims to be more talented than that person). Eat your heart out—I got tickets to the concert and you didn't! Look at how well I dance now—Gene Kelly, eat your heart out!
See also: eat, heart, out

eat one's heart out

Feel bitter anguish, grief, worry, jealousy, or another strong negative emotion. For example, She is still eating her heart out over being fired, or Eat your heart out-my new car is being delivered today. This hyperbolic expression alludes to strong feelings gnawing at one's heart. [Late 1500s]
See also: eat, heart, out