to feel very unhappy, especially because you want sb / sth you cannot have; used to compare two things and say that one of them is better
eat your heart out (for sb / sth)British
to feel very unhappy, especially because you want sb / sth you cannot have
eat your heart out!informal
used to compare two things and say that one of them is better
Look at him dance! Eat your heart out, Fred Astaire (= he dances even better than Fred Astaire).
Definitions from the Oxford Advanced Learner's Dictionary, 9th edition