eat one's heart out

Disputed. Three schools of thought exist: * From "This will eat your heart out.", suggesting that the recipient of the taunt will have their heart, the core of their being, eaten out with desire, bitterness, or pain. * From the 16th century "to eat one's own heart" (to suffer in silence from anguish or grief), possibly from the Bible "to eat one's own flesh" (to be lazy). The phrase "to eat one's heart out" appears as a formulaic phrase in the Iliad, meaning to experience extreme grief. (For instance, Iliad.24.128, and many other locations.) * When used as the taunt "Eat your heart out, [someone]!" a suggestion that the recipient of the taunt "eat up" as much as they like. Figuratively more akin to "experience me besting you."

• "The Brazilians are eating their hearts out over their defeat by Germany in the World Cup."
• "Eat your heart out, pal! We won the title!"
• "People in ordinary life who pine for want of something to do and to care about, are subject to ailments which are called “the maladies of ennui.” These are real diseases, though arising from moral causes. The brain wears upon itself, the nerves become disordered, and the various bodily functions are disturbed, just as in the case of a restless prisoner who is said to “eat his heart out” in captivity."
• "Castles where [August the Strong] imprisoned this discarded mistress or that - one of them, who persisted in her claim to a better title, forty years, it is said, poor lady! The narrow rooms where she ate her heart out and died are still shown."
• "Jon: We got a postcard from Doc Boy! He’s vacationing in Loogieville, Indiana…says he had his picture taken with the world’s largest corn cob Garfield: Eiffel Tower, eat your heart out"