impartial
Fair and not favoring one side over another.
To be impartial means to be fair and unbiased, not favoring one side over another. An impartial person makes decisions based on facts and rules rather than personal feelings or preferences.
Think of a referee in a soccer game. A good referee stays impartial, calling fouls on either team when they break the rules. It wouldn't matter if the referee's own child played on one of the teams: an impartial referee would still make fair calls. If the referee started favoring one side, giving them easier penalties or ignoring their fouls, they would no longer be impartial.
Teachers try to be impartial when grading papers, judging each student's work by the same standards. Judges in courtrooms must remain impartial, listening carefully to both sides before making a decision. Even friends can be impartial: if two of your friends are arguing about whose turn it is to choose the game, you might help by being an impartial observer who simply reports what happened.
Being impartial can be challenging because everyone has opinions and feelings. But impartiality matters whenever fairness is important: in competitions, in schools, in courts, and in everyday disagreements. The opposite of impartial is biased or partial, which means unfairly favoring one side.