Disinterested is an adjective.
Meanings: unbiased; fair-minded; neutral; impartial.
Uninterested is an adjective.
Meanings: indifferent; impassive; unconcerned; remote; aloof.
1. It was only after testing the referees during national level games that they were selected for the international tournament as they needed to be disinterested in their decisions.
2. The special invitee seemed uninterested in the proceedings of the program, seeming to doze off from time to time.
3. The concert was an uninteresting presentation and left the audience totally disinterested.