Misconduct is behavior that breaks rules, violates standards, or betrays the trust placed in someone, especially when they hold a position of responsibility. When a referee shows misconduct by favoring one team unfairly, they're abusing their role as a neutral judge. When a scientist commits misconduct by inventing data instead of recording real results, they're betraying the basic principles of honest research.

The word usually applies to people in positions where others count on them to do the right thing: teachers, athletes, doctors, police officers, business leaders, or public officials. A student who skips homework might get in trouble, but that's not usually called misconduct. A teacher who grades students based on personal favorites rather than their actual work would be guilty of misconduct because they're violating the trust and responsibility that comes with their position.

Misconduct differs from an honest mistake. When someone commits misconduct, they typically know they're doing something wrong but choose to do it anyway. A soccer player who deliberately trips an opponent commits misconduct and might receive a yellow card. A banker who steals from customers commits serious misconduct and could face criminal charges.

Organizations often have formal rules about misconduct, with specific consequences depending on how serious the violation is. Professional misconduct can end careers, because people lose the credentials and trust needed for their work.