indifferent
Not caring much which choice or outcome happens.
Indifferent means not caring one way or the other about something. When you're indifferent to which movie your family watches, you genuinely don't mind the choice. It means feeling neither excited nor disappointed, neither for nor against.
Being indifferent is different from pretending not to care when you actually do. If your friend asks whether you want pepperoni or cheese pizza and you're truly indifferent, both options sound equally fine to you. But if you secretly want pepperoni and just say “whatever,” that's not really indifference.
Sometimes indifference can be neutral or even helpful. When a judge makes a decision in court, she should be indifferent to which side wins and only care about following the law fairly. Scientists try to remain indifferent to what their experiments prove, letting the evidence lead them wherever it goes.
But indifference can also mean a troubling lack of concern. If someone is indifferent to another person's suffering, they don't seem to care about helping. When a student becomes indifferent to their schoolwork, they've stopped caring whether they do well or poorly. This kind of indifference can signal that something's wrong, since caring about things and people around us usually matters.