characterized by a lack of partiality
"a properly indifferent jury"
"an unbiased account of her family problems"
Impartial or without bias or prejudice.
"The judge was praised for being unbiased during the trial, treating both sides of the argument equally."
In plain English: Unbiased means having no preference for or against anything, so your opinion is fair and not influenced by personal feelings.
"The judge is known for being unbiased in every case she hears."
The word unbiased is formed by adding the prefix un- to biased, meaning it simply means not having a bias. It entered English as a direct combination of these two elements to describe impartiality.