IPA: /dɪsˈɪntrəstɪdli/
KK: /dɪsˈɪntrəstɪdli/
In a way that shows no personal interest or bias; fairly and impartially.
She listened disinterestedly to the arguments on both sides before making her decision.
Disinterestedly → It is formed from "dis-" (meaning apart or away) and "interested" (from Latin "interesse", meaning to be between or to concern). The suffix "-ly" indicates the manner of the action. Thus, "disinterestedly" means to act in a manner that is not influenced by personal interest or concern, essentially being impartial or unbiased.
Think of acting 'apart' ('dis-') from any 'concern' ('interesse') — that's why disinterestedly means to act without personal bias.