Unfair means not treating people equally or by the same rules, giving some an advantage that others don't get. When a teacher gives one student extra time on a test but not the others, that's unfair. When a referee ignores one team's rule violations but penalizes the other team, players will protest that it's unfair.

Something is unfair when it violates our sense of justice and equality. If your older sibling gets to stay up an hour later than you do even though you're the same age, you'd probably call that unfair. If one child has to do all the chores while another does none, that feels unfair.

The word carries a feeling of frustration or indignation. When kids say “That's not fair!” they're pointing out that someone broke an unspoken rule about how people should be treated. Sometimes life itself feels unfair: a hardworking student might study for hours and still struggle with a subject that comes easily to someone who barely studies.

Unfair is different from difficult or disappointing. A hard math test isn't unfair if everyone gets the same questions and time. Losing a close game isn't unfair if both teams followed the rules. Something becomes unfair when the rules, opportunities, or treatment aren't equal for everyone involved.