If you're disinterested, you're unbiased; you're out of the loop. But if you're uninterested, you don't give a hoot; you're bored. These two words have been duking it out, but the battle may be over for uninterested. Heavyweight disinterested has featherweight uninterested on the ropes.
If you want a disinterested, or unbiased opinion, don't ask your ex-boyfriend if you can ask his brother out. He will not be disinterested. Disinterested means impartial, having no bias or profit from something:
There is no convincing evidence for this convoluted advice, disinterested researchers say. (New York Times)
Disinterested service is a virtue ordinary human intelligence cannot grasp. (F.E. Mills)
Uninterested means neutral or indifferent, having no interest in something. Once your former sweetheart has a new girlfriend, he might be bored, or uninterested, enough for you to ask him about his cute brother. Here are some uninterested examples:
The coach had put some thoughts on paper and gave his friend the name of a possible publisher who turned out to be uninterested. (New York Times)
"He was dedicated to the automobile," Mr. Joyce said, and uninterested in mass transit. (New York Times)
If your ex is disinterested enough to give you his brother's number, he's over you and unbiased. If the cute brother is uninterested and doesn't call you back, then he's just not into you. But know this: disinterested appears almost twice as often as uninterested, and a quick scan shows that disinterested is frequently used to mean uninterested.Uninterested is down and will soon be counted out. Just like that date.