Writing in Cultural Amnesia: Necessary Memories from History and the Arts, the great Clive James points out that, “as Kingsley Amis acutely noted, the person who uses ‘disinterested’ for ‘uninterested’ is unlikely to see your article complaining about the point, because the person has never been much of a reader anyway.”
What? They’re not synonyms?
The first definition of disinterested in my copy of The American Heritage Dictionary of the English Language (fourth ed.) reads “Free of bias and self-interest; impartial”; “Not interested; indifferent” reads the second. A note in the text, however, mentions that 89 percent of the dictionary’s usage panel rejected the second definition back in 1988, only a slight decrease from the 93 percent who disapproved in 1980. An online search reveals that the number was 88 percent in 2001 and 86 percent in 2013.
Experts agree: they’re not synonyms. So what gives? I wish I knew. For now, I’m sticking with my go-to source in all matters related to English, who writes, “A bored person is uninterested. Do not confuse this word with the much rarer ‘disinterested,’ which means ‘objective, neutral.'” That’s good enough for me.