* 개인적(인) (a) = personal. (개인 = an individual person). 개인적 취향 = personal tastes. * 사적(인) (a) = private (i.e. not official or for an organization or community. 사 = private, 공 = public). - 사적인 일에 회사 차량을 사용할 수 없습니다 = You can't use a company vehicle for private matters. * 사정 (n) = personal matter/affair - it refers to a real matter that affects the person without naming it exactly. - 집에 사정이 있어서 나갈 수가 없어요 = I have something at home that keeps from going out. - 장관은 개인(적) 사정을 이유로 사임했다 = The minister has resigned for reasons of personal matters.

How is 개인적, 사적 used differently ? Does one have more of a negative nuasance?

개인적, 사적 - These two words are equivalent in meaning. but, they are differently used depending on the context.

I don't think there's any difference btw 개인적=사적 (personal, private). 사정 = could be 'a reason', 'a situation'....