indifference
A lack of care, interest, or strong feeling about something.
Indifference is the state of not caring about something or someone, of feeling no interest, concern, or emotion about it. When you're indifferent to which movie your family watches, you genuinely don't mind either choice. When someone shows indifference to another person's feelings, they act as if those feelings don't matter or barely register.
Indifference is colder than dislike. If you dislike brussels sprouts, you have strong feelings about them. If you're indifferent to brussels sprouts, you barely notice them on your plate. They simply don't matter to you one way or the other.
The word often carries a negative weight, especially when it involves people. A teacher who shows indifference to struggling students doesn't actively harm them, but their lack of concern can be just as damaging. When someone is indifferent to injustice, they witness unfairness but feel no urge to help or speak up.
The opposite of love isn't always hate. Sometimes it's indifference, that hollow space where no feeling exists at all. Scientists and judges, however, need a kind of positive indifference: they must remain impartial and unbiased, setting aside personal feelings to focus on facts and fairness. In those cases, indifference can serve an important purpose.