I couldn't care less
US /aɪ ˈkʊdnt kɛr lɛs/
UK /aɪ ˈkʊdnt kɛr lɛs/

1.
no me importa en absoluto, me da igual
used to express that one does not care at all about something
:
•
He was complaining about his new car, but I couldn't care less.
Se quejaba de su coche nuevo, pero a mí no me importaba en absoluto.
•
Whether they come or not, I couldn't care less.
Vengan o no, a mí no me importa en absoluto.