Define disinterested, please.

Not having my OED handy, I've always understood "disinterested" to mean one is impartial and has no investment (or "interest" in the legal sense) in the outcome of a contest between parties; the US colloquialism, I suspect, is "to have no dog in the fight" while the UK version might be "to have no axe to grind". One might still be interested in the outcome, however, and want to know the result.

"Uninterested", by contrast, is understood to mean one couldn't care less about the result. You could expect an umpire or referee in any contest to be disinterested but would be disappointed if they were uninterested.

Cheers, Rowan