eat (one's) heart out
To feel bitter anguish or grief

[TahlilGaran] Dictionary of Contemporary English ▲

eat one's heart out
PINE, long, ache, brood, mope, fret, sigh, sorrow, yearn, agonize, grieve, mourn, lament

[TahlilGaran] Dictionary of Contemporary English ▲

eat heart out
eat (your) heart out
you should be sorry for the choices you have made.
I thought I'd become famous, and I could say "Eat your heart out" to every girl I'd ever gone out with.

Usage notes: usually said as if it were an order, as in the example

[TahlilGaran] English Idioms Dictionary ▲

eat one's heart out
to be envious of someone or something, to be very sad; to suffer from excessive longing or envy
I ate my heart out when I saw my friend and his new bicycle.

"You can eat your heart out. I am going to Hawaii for three weeks!"

"You can eat your heart out but I will not give you a piece of this chocolate cake."

[TahlilGaran] English Idioms Dictionary ▲

eat one's heart out
v. phr. To grieve long and hopelessly; to become thin and weak from sorrow.
For months after her husband's death, Joanne simply ate her heart out.
We sometimes hear of a dog eating its heart out for a dead owner.

[TahlilGaran] English Idioms Dictionary ▲