The concepts are not hard to understand and it is not uniquely French, far from it. That said, I cannot think of a single-word equivalent in English.

I can't think of a single-word translation for schadenfreude either, but that doesn't mean anything

TIL Epicaricacy, from ancient Greek ( it was unlikely that the Ancient Greeks didn't have a word for something such a human flaw.

"epicaricacy" fails the simplest test for word-ness: it's never [0] used with the expectation of being understood without explanation. (Nor ever has been, according to Wiktionary.) It seems to have been one of the earliest Nihilartikels.

It could still be adopted as a learnèd (read: pretentious) borrowing from Greek, of course, but in that case it would be spelled epicharicacy.

[0] Edit: Well, hardly ever. https://en.wiktionary.org/wiki/Citations:epicaricacy#English

Except he provided an inaccurate translation so it seems to me that the concept is not so well understood...

IMHO it is indeed untranslatable in the sense that there is no single word in English with the same meaning so that a translation requires a description (illustrated by my quote from Wikipedia that spends a whole paragraph explaining what it means).