Indifferent, unconcerned, incurious, aloof, detached, uninterested, disinterested mean not feeling or showing interest, especially natural or normal interest.
Indifferent is often used in place of the other and more specific terms. It may imply neutrality of attitude arising either from a lack of bias, prejudice, or predilection when two or more persons or things are considered or from a lack of feeling for or against a particular person or thing.
Unconcerned implies indifference such as arises from unconsciousness, insensitiveness, or selfishness which prevents one from being moved, worried, or made solicitous.
Incurious implies indifference arising from a lack of intellectual interest or normal curiosity; it often suggests incapacity because of temperament or state of mind.
Aloof and especially its derivative aloofness stress indifference that is the natural result of feeling apart or at a distance from someone or something (as from temperamental reserve, a sense of superiority, or an aversion to the inferior).
Detached often implies a commendable aloofness which is the result of freedom from prejudices or of selfish concern for one’s personal interests. Sometimes it distinctively suggests a point of view or way of looking at persons or things as though they bear no relation to one’s own life.
Uninterested is the most neutral of these terms and in itself suggests nothing beyond the fact of a lack of interest.
Disinterested though increasingly interchangeable with uninterested, in its more discriminative use suggests a freedom from thought of personal advantage or interest that permits one to detect the truth, to tell the truth, or to judge truly.