Can't sub for Bel, but can tell you of a colloquial French expression: Je m'en fiche. Meaning, more politely, "the hell with it"; less politely, "f..k it."

Then you get creative with this expression. One character in a book I read got so frustrated over a situation he shouted, "Je m'en fiche. Je m'en refiche, et je m'en contrefiche." (The same expression with intensifiers.)