Uninterested: Used to describe someone who is not engaged and bored. A great example would be me when someone is talking about Kim Kardashian. I don't care, and would try to disengage from the conversation.
I put together two pictures that will hopefully help you remember the difference. Judge cat is disinterested, meaning that he will make a decision not influenced by his feelings. Bored cat does not know why you are looking at him, and does not care to learn why - he is uninteretsed.