An adversary is someone who opposes you or stands against you in a competition, conflict, or debate. In a chess match, your adversary sits across the board trying to outmaneuver your pieces. In a spelling bee, your adversaries are the other students competing for the championship. When two lawyers argue opposite sides of a case in court, they're adversaries.

An adversary is someone you take seriously, someone whose challenge makes you work harder and think more carefully. In The Phantom Tollbooth, Milo faces adversaries like the Terrible Trivium, who tries to stop him from rescuing the princesses. In sports, a worthy adversary pushes you to play your best game.

You might have adversaries in a debate tournament, a business competition, or even a friendly rivalry with another school. The relationship isn't necessarily hostile: athletes often respect their adversaries and shake hands after competing. Sometimes facing a skilled adversary teaches you more than easy victories ever could.