The following is an excerpt from The Curmudgeon’s Guide to Getting Ahead, in which author Charles Murray discusses words with meanings that have changed — and not always for the better.
Disinterested used to mean uninterested.
The meaning of disinterested is “free of bias and self-interest.” It is essential that a judge be disinterested, for example. Disinterested does NOT, repeat NOT, mean “lack of interest” or “uninterested.” I put this so emphatically because we’re not talking just about proper usage. Disinterest used in its correct sense is on its last legs—I’ve been appalled to see it misused in articles in the Washington Post and other major publications. English does not have another word that conveys the meaning of disinterested as economically. If we lose the distinctive meaning of the word, we have measurably degraded our ability to express ourselves in English.