Traditionally, the words disinterested and uninterested have different meanings. While cautious writers still observe this distinction in formal writing, other people use these two terms in the same manner nowadays. This may be understandable since both prefixes dis- and un- mean “not.”
The term disinterested is an adjective that traditionally means “not influenced by considerations of personal advantage.”
“Mr Walsh is not exactly a disinterested observer.”
The Economist“Presidents, in recognizing that responsibility accompanies this latitude, have traditionally turned their business and financial interests over to a disinterested third party.”
Bloomberg“Even if he had a disinterested party manage it, he’d still know what his assets were and he could undertake policies that would make those assets more valuable”
NBC News
The confusion between the two terms may be attributed to disinterested‘s more popular use as an adjective denoting “having or feeling no interest in something.”
“Role of IPU: War industry-boosting nations disinterested in peace: Rabbani”
The Express Tribune“City disinterested in managing councillor conflict”
The Peterborough Examiner“Man City pedestrian and disinterested in embarrassing loss to Southampton”
ESPN
This meaning of disinterested is very similar with uninterested, which is an adjective referring to “having or showing no feeling of interest; indifferent” or being “not personally concerned in something.”
“Donald Trump Declares Gay Marriage Debate ‘Settled,’ Uninterested in Overturning Supreme Court Decision”
The Christian Post“Conor McGregor uninterested in facing undefeated Khabib Nurmagomedov”
FanSided“Biden uninterested in serving in Clinton administration”
Dhaka Tribune
In the traditional context, a disinterested person is someone who is impartial or unbiased in a particular issue or case while an uninterested person is someone who is unconcerned or indifferent about the said issue or case. While many writers still follow the traditional use of disinterested, it is not uncommon to see the word being used in place of uninterested nowadays. To avoid confusion, you may use synonyms of disinterested in its traditional sense, such as unbiased, impartial, and neutral.