The following is a definition of equanimity, and how equanimity differs from indifference or apathy. The entire quote comes from Shinzen Young:
“Many people get confused about what equanimity is and what it isn’t. Here are some examples that may help clarify.
Equanimity can be deepened by relaxing tension around pain, such as the pain of a broken leg. But equanimity does not mean that you don’t care about getting proper medical attention, such as getting a cast.
Equanimity means opening up to angry sensations that may arise during an argument. But equanimity does not mean that you should stay in a bad relationship.