used to emphasize rudely that you are not interested in or worried about something or someone

"Mike's really fed up about it." "I couldn't care less." “迈克烦透这个了。”“我根本不在乎。”

"Sophie won't be happy with the new arrangements." "I couldn't care less, to be honest."

"What will James think of us?" "Well, I couldn't care less."

I couldn't care less if she's offended.

Susie's always trying to impress him whereas I couldn't care less what he thinks of me.

See also: care verb (WORRY)