Someone who is dispassionate is calm and reasonable, and not affected by emotions.
例句
We, as prosecutors, try to be dispassionate about the cases we bring...作為檢察官，我們對經手的案件會盡力做到不偏不倚。He spoke in the flat, dispassionate tone of a lecturer.他以一個講師般平板、不動感情的口吻說話。
英英詞典釋義
Adverb
1. in an impartially dispassionate manner;
"although he was looking at the other girl, he did so dispassionately"