"impartial" in the adjective sense
showing lack of favoritism
"the cold neutrality of an impartial judge"
2. unprejudiced, impartial
free from undue bias or preconceived opinions
"an unprejudiced appraisal of the pros and cons"
"the impartial eye of a scientist"
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License