heartache

meaning in plain English

A deep, painful sadness in your chest because of something that happened or someone you lost.

for example

After his dog died, he spent weeks dealing with heartache and couldn’t stop crying.

Imagine holding a heavy rock in your chest that won’t go away—no matter how much you try to push it out, it just sits there. That’s heartache: the weight of love or loss you can’t shake off, even when you want to.