Definition of I (or he, she, etc.) couldn't care less in English:

I (or he, she, etc.) couldn't care less

phrase

informal
  • Used to express complete indifference.

    • ‘he couldn't care less about football’
    • ‘Those on the right want more drilling and couldn't care less about conservation.’
    • ‘By saying nothing to you about your achievements, it can seem to you as if they couldn't care less.’
    • ‘It was good to be in a crowd of people who couldn't care less about blogging for part of the weekend.’
    • ‘The other boy wanted nothing more than the object in her hand, and couldn't care less what happened to her.’
    • ‘She couldn't care less about Richie any more than we could.’
    • ‘Today, she couldn't care less about the trappings of success.’
    • ‘Look, I couldn't care less if the guy stealing my newspaper is morally conflicted.’
    • ‘But it was the manner in which he asked that made me realize he couldn't care less.’
    • ‘But on any given game night if we don't get a guy his tickets quickly and efficiently, he couldn't care less about that issue.’
    • ‘Sadly, it didn't matter, since my friends and mother couldn't care less which one it was.’
    inattentive, incautious, negligent, remiss
    unstudied, artless, casual, effortless, unconcerned, nonchalant, insouciant, languid, leisurely, informal