A sore loser is someone who reacts badly to losing a game or a competition. Synonyms for this term include "bad sport," "poor loser," "sourpuss," "whiner," "crybaby," "sulk," "grump," and "fussbudget." These terms all describe a person who has difficulty accepting defeat and may throw a fit or make excuses for their loss. It's important to remember that losing is a natural part of competition and games, and being a good sport and showing sportsmanship is essential to building positive relationships and enjoying the activity itself.