Disinterested means having nothing to gain, and therefore able to judge fairly. An impartial referee, not a bored one.
This is one of the words careful writers fight over. Strictly, disinterested means impartial and uninterested means bored, and mixing them up loses a useful distinction, since a judge should be disinterested and had better not be uninterested. The loose sense meaning bored is now extremely common and dictionaries record it. The noun disinterest is ambiguous for exactly the same reason, so impartiality is the safer word.
1adjectivedisinterestedImpartial, with nothing personal to gain.
“They wanted disinterested advice, not a sales pitch.”
Proto-Indo-European
*h₁es-
English, today
disinterested
From disinterest + -ed, or from dis- + interested.
Etymology from Wiktionary, CC BY-SA